Programmable Thermostat with Ramp

[Whoey Louie]

On Sunday, January 12, 2020 at 2:28:19 PM UTC-5, Winfield Hill wrote:

Rick C wrote...

Disabling the backup heat won't necessarily work anyway.
I had a heat pump backed by an oil burner. The oil burner
stopped lighting one day and the system just didn't work.
Seems they turn off the heat pump when running the back
up heat and if the backup heat doesn't work you are then
stuck with no heat even though the primary heat works!

Yes, our system works that way.


--
Thanks,
- Win

This is likely due to the backup being OIL HEAT, not electric. And
many of these things can also be set by the installer, who knows what
some incompetent bozo did. But the system under discussion has
electric resistance heat. It would be incredibly stupid to have a
heat pump system designed where if the heat pump can't heat fast
enough, it shuts off the heat pump and just uses electric resistance
heating. Why on earth would any rational designer do that? You
have the heat pump putting out 4x the heat for the same energy used
and you're going to turn it off? Not only will it take longer to
get the temp up without the heatpump, it will also cost more.

 

[Whoey Louie]

On Monday, January 13, 2020 at 2:30:50 AM UTC-5, Jasen Betts wrote:

On 2020-01-12, Rick C <gnuarm.deletethisbit@gmail.com> wrote:
On Saturday, January 11, 2020 at 11:30:49 PM UTC-5, Jasen Betts wrote:
On 2020-01-11, Rick C <gnuarm.deletethisbit@gmail.com> wrote:
I am using a programmable thermostat to turn off the heat and/or air conditioning during the peak usage times as set by the ToU billing with my utility. The problem I have is the heat pump not ramping up the temperature fast enough when it comes back on and the backup straight electric heat coming on. This uses maybe three times the amount of electricity during the time it takes to get up to temperature.

I don't know if this is caused by the thermostat or the heat pump itself. I'm wondering if anyone makes a programmable thermostat that deals with this issue. If the problem is caused by the thermostat not letting the heat pump run long enough that is easy to fix. If the problem is caused by the heat pump itself, then the way to deal with it is for the thermostat to run the heat pump in bursts short enough to keep the back up heat from running.

Is there anthing you can do to make the heat pump produce more heat?
(have you found anything, or am I just restating your question?)

I'm not sure what you are asking. Heat pumps tend to be on/off arrangements. I've seen something about two stage heat pumps, but whatever that is, I don't have one. So the way to get more heat out of the pump is to run it longer. But that's not the issue. The heat pump isn't "straining" or undersized. It just has to run for a while in order to bring the temperature up and the thermostat is designed to treat that as a condition where it needs to run the backup heat.

Like some of the other posters, I have no idea where you are going with this.


What is the interface from the thermostat to the heat-pump? is it just
one wire for 24V AC, one wire for heat, one wire for fan, and one wire
for ground?

I haven't taken it apart, but I'm sure it's the standard heat pump with electric backup wiring arrangement. There are actually a number of wires, one for heat, one for cooling, one to run the fan, one to bring in power and I believe a common.

I would only care about that if I want to roll my own thermostat.

Again, where would you be going with this?

I'm trying to identify the problem space.

If the thermostat can't call for extra heat (more neat the regular
heat) it also can't control what the heat-pump does to provide the heat.

Agree. The typical thermostats available on the market do control
the aux heat though. I bet Rick's does too.

Perhaps the compressor is reading something into it length of the
heat command. maybe if you blip the heat command off for 30 seconds
every 15 minutes it won't fire up the resistive heater.

IDK, but it's possible. For example, two stage gas furnaces can do
something similar. Ideally whether it fires at high stage or low should
be done by the thermostat, because only it has the complete information,
which is the desired temp and current temp. But it takes an extra wire
for two stages and there may not be one available. So, two stage furnaces
have a setting where instead, the furnace makes the call. If set to that
mode, if the furnace runs more than a certain number of minuts, ~7, then
it will switch to high. Obviously inferior to the other method, which
can put it into high immediately.

If it can call for extra heat you'll need a script that queries
the thermostat for the current temperature (I expect a smart
thermostat knows the current temperature) and then puts the set point
just a few degrees warmer so that the thermostat doesn't go into rush
mode and ask for extra heat (just ask for regular heat).

--
Jasen.

Yes, I suggested that too. With a wifi computer and a program running on
a PC, it could monitor and control it. But first I would download the install
manuals for modern thermostats and see if they address this. You would think
at least some would. The obvious way would be with a setting where the
thermostat estimates how long it will take to get to the target temp and
if that takes longer than X minutes, then it adds aux heat. And X is
programmable. This seems like something that some manufacturers would
have addressed. They could also have something related to time of day
for customers that have different rates at different times of day.
Like if the electric is cheap, or it's 6am and you want to make sure the
house is warm when you get up, maybe you want a one hour period, if it's
expensive or afternoon you can live with 3 hours.

 

[amdx]

On 1/11/2020 11:03 AM, Rick C wrote:

On Saturday, January 11, 2020 at 8:49:50 AM UTC-5, Winfield Hill wrote:
Rick C wrote...

My heatpump runs anytime the temperature is above 40F
= 4.4C (this is adjustable). The thermostat calls for
"aux" heat (oil furnace) when the outside temperature
is below that. When aux heat runs, the heatpump is
entirely off. It's a 2014 Carrier "edge" thermostat.

Yes, you have posted about the limitations of your heatpump before. How is that relevant?

I suspect if you check with someone who knows, your backup heat will also run under two other conditions. One is the system detects ice on the outside coils. With a 40 degree cut off, your system might not worry with deicing. The other condition is when the system runs long enough that it decides the heat pump is not doing the job and switches to backup heat. Opps, another condition is if the inside temperature drops too far bellow the set temperature.

The first heat pump I owned was very, very simple. It had a two bulb thermostat. Set the temperature and bulb 1 would control the heat to keep the temperature. But if the room (hallway as the case may be) temperature dropped too far the second bulb switch would close and the backup heat would come on.

That is the condition I am trying to avoid with a thermostat which ramps the temperature up slowly enough to not kick in the backup heat.

I don't know of any heat pump that isn't set to work that way. Ask your installer. With the last system I bought I found I could not even get info from the company who made it. They always referred me to the "installer", like I was not worthy of information.

My thinking is, the thermostat sees a high delta between the house
temperature and the set temperature. In order to correct that (for your
comfort) it turns on both heat pump and auxiliary heat.

I suspect there is a wire from the thermostat to the control board,
that develops an output when there is a high delta, this output tells

the control board to turn on Auxiliary heat.

The truth may lie elsewhere, but that's my analysis.


On page 47 of the Thermostat manual, if this is the manual,

http://www.utcccs-cdn.com/hvac/docs/1009/Public/04/OM-TPPACA-01.pdf
It says,

"SPECIAL FEATURES Hybrid Heat (heat pump with a furnace system
only)This thermostat works with the Carrier Hybrid Heat systems
offering maximum comfort and economy by automatically controlling
whether your system delivers heating with the heat pump, with the
furnace, or with both options working together."


Page 52
Hybrid Heat (heat pump with a furnace system only)page 47........This
Carrier heating and cooling system concept offers maximum
comfort and economy. When a Hybrid Heat system is installed,
the thermostat automatically controls whether your system delivers
heating with the heat pump, with the furnace,or with both options
working together.
Mikek

 

[John Robertson]

On 2020/01/12 11:28 a.m., Winfield Hill wrote:

Rick C wrote...

Disabling the backup heat won't necessarily work anyway.
I had a heat pump backed by an oil burner. The oil burner
stopped lighting one day and the system just didn't work.
Seems they turn off the heat pump when running the back
up heat and if the backup heat doesn't work you are then
stuck with no heat even though the primary heat works!

Yes, our system works that way.

Heat pumps don't work well below around -4C due to the coefficient of
performance, so unless it is geothermal they often need to be shut down
usually due to icing.

https://www.nordicghp.com/2017/01/heat-pump-effective-temperature-range/

John :-#)#

 

[Rick C]

On Monday, January 13, 2020 at 12:37:39 PM UTC-5, amdx wrote:

On 1/11/2020 11:03 AM, Rick C wrote:
On Saturday, January 11, 2020 at 8:49:50 AM UTC-5, Winfield Hill wrote:
Rick C wrote...

My heatpump runs anytime the temperature is above 40F
= 4.4C (this is adjustable). The thermostat calls for
"aux" heat (oil furnace) when the outside temperature
is below that. When aux heat runs, the heatpump is
entirely off. It's a 2014 Carrier "edge" thermostat.

Yes, you have posted about the limitations of your heatpump before. How is that relevant?

I suspect if you check with someone who knows, your backup heat will also run under two other conditions. One is the system detects ice on the outside coils. With a 40 degree cut off, your system might not worry with deicing. The other condition is when the system runs long enough that it decides the heat pump is not doing the job and switches to backup heat. Opps, another condition is if the inside temperature drops too far bellow the set temperature.

The first heat pump I owned was very, very simple. It had a two bulb thermostat. Set the temperature and bulb 1 would control the heat to keep the temperature. But if the room (hallway as the case may be) temperature dropped too far the second bulb switch would close and the backup heat would come on.

That is the condition I am trying to avoid with a thermostat which ramps the temperature up slowly enough to not kick in the backup heat.

I don't know of any heat pump that isn't set to work that way. Ask your installer. With the last system I bought I found I could not even get info from the company who made it. They always referred me to the "installer", like I was not worthy of information.


My thinking is, the thermostat sees a high delta between the house
temperature and the set temperature. In order to correct that (for your
comfort) it turns on both heat pump and auxiliary heat.

I suspect there is a wire from the thermostat to the control board,
that develops an output when there is a high delta, this output tells

the control board to turn on Auxiliary heat.

The truth may lie elsewhere, but that's my analysis.


On page 47 of the Thermostat manual, if this is the manual,
http://www.utcccs-cdn.com/hvac/docs/1009/Public/04/OM-TPPACA-01.pdf
It says,

"SPECIAL FEATURES Hybrid Heat (heat pump with a furnace system
only)This thermostat works with the Carrier Hybrid Heat systems
offering maximum comfort and economy by automatically controlling
whether your system delivers heating with the heat pump, with the
furnace, or with both options working together."


Page 52
Hybrid Heat (heat pump with a furnace system only)page 47........This
Carrier heating and cooling system concept offers maximum
comfort and economy. When a Hybrid Heat system is installed,
the thermostat automatically controls whether your system delivers
heating with the heat pump, with the furnace,or with both options
working together.
Mikek

Doesn't say anything about electric back up vs. oil, etc...

One very good reason to not run the heat pump with the backup electric heat is the power required. They have separate breakers, but the electric coils in my house are 10 kW or 40 amps requiring a 50 amp circuit. The outside unit would require a 30 amp breaker. Just how much can you wire into a panel before it becomes a problem? If the kitchen were drawing 5 kW or more, the hot water heater was running at 10 kW (or more) and the dryer was running at 8 kW, that's pretty durn close to the house hold max. Throw in an iron fire up the microwave and a few light bulbs and the main breaker might blow. One of my other houses, only having 100 amp service, might have blown the main breaker before the dryer was turned on, but for the fact it has oil backup.

--

Rick C.

---- Get 1,000 miles of free Supercharging
---- Tesla referral code - https://ts.la/richard11209

 

[amdx]

On 1/13/2020 12:08 PM, Rick C wrote:

On Monday, January 13, 2020 at 12:37:39 PM UTC-5, amdx wrote:
On 1/11/2020 11:03 AM, Rick C wrote:
On Saturday, January 11, 2020 at 8:49:50 AM UTC-5, Winfield Hill wrote:
Rick C wrote...

My heatpump runs anytime the temperature is above 40F
= 4.4C (this is adjustable). The thermostat calls for
"aux" heat (oil furnace) when the outside temperature
is below that. When aux heat runs, the heatpump is
entirely off. It's a 2014 Carrier "edge" thermostat.

Yes, you have posted about the limitations of your heatpump before. How is that relevant?

I suspect if you check with someone who knows, your backup heat will also run under two other conditions. One is the system detects ice on the outside coils. With a 40 degree cut off, your system might not worry with deicing. The other condition is when the system runs long enough that it decides the heat pump is not doing the job and switches to backup heat. Opps, another condition is if the inside temperature drops too far bellow the set temperature.

The first heat pump I owned was very, very simple. It had a two bulb thermostat. Set the temperature and bulb 1 would control the heat to keep the temperature. But if the room (hallway as the case may be) temperature dropped too far the second bulb switch would close and the backup heat would come on.

That is the condition I am trying to avoid with a thermostat which ramps the temperature up slowly enough to not kick in the backup heat.

I don't know of any heat pump that isn't set to work that way. Ask your installer. With the last system I bought I found I could not even get info from the company who made it. They always referred me to the "installer", like I was not worthy of information.


My thinking is, the thermostat sees a high delta between the house
temperature and the set temperature. In order to correct that (for your
comfort) it turns on both heat pump and auxiliary heat.

I suspect there is a wire from the thermostat to the control board,
that develops an output when there is a high delta, this output tells

the control board to turn on Auxiliary heat.

The truth may lie elsewhere, but that's my analysis.


On page 47 of the Thermostat manual, if this is the manual,
http://www.utcccs-cdn.com/hvac/docs/1009/Public/04/OM-TPPACA-01.pdf
It says,

"SPECIAL FEATURES Hybrid Heat (heat pump with a furnace system
only)This thermostat works with the Carrier Hybrid Heat systems
offering maximum comfort and economy by automatically controlling
whether your system delivers heating with the heat pump, with the
furnace, or with both options working together."


Page 52
Hybrid Heat (heat pump with a furnace system only)page 47........This
Carrier heating and cooling system concept offers maximum
comfort and economy. When a Hybrid Heat system is installed,
the thermostat automatically controls whether your system delivers
heating with the heat pump, with the furnace,or with both options
working together.
Mikek

Doesn't say anything about electric back up vs. oil, etc...

One very good reason to not run the heat pump with the backup electric heat is the power required.

Why are you arguing that. I understand why you are trying to shut down
the auxiliary heat.

They have separate breakers, but the electric coils in my house are 10
kW or 40 amps requiring a 50 amp circuit. The outside unit would
require a 30 amp breaker. Just how much can you wire into a panel
before it becomes a problem? If the kitchen were drawing 5 kW or more,
the hot water heater was running at 10 kW (or more) and the dryer was
running at 8 kW, that's pretty durn close to the house hold max. Throw
in an iron fire up the microwave and a few light bulbs and the main
breaker might blow. One of my other houses, only having 100 amp
service, might have blown the main breaker before the dryer was turned
on, but for the fact it has oil backup.

Not helpful info.

So, do you think or can you find out, if the Thermostat has a separate
output when the thermostat has a high differential to fire up the oil
furnace?
Mikek

 

[Rick C]

On Monday, January 13, 2020 at 1:52:26 PM UTC-5, amdx wrote:

On 1/13/2020 12:08 PM, Rick C wrote:
On Monday, January 13, 2020 at 12:37:39 PM UTC-5, amdx wrote:
On 1/11/2020 11:03 AM, Rick C wrote:
On Saturday, January 11, 2020 at 8:49:50 AM UTC-5, Winfield Hill wrote:
Rick C wrote...

My heatpump runs anytime the temperature is above 40F
= 4.4C (this is adjustable). The thermostat calls for
"aux" heat (oil furnace) when the outside temperature
is below that. When aux heat runs, the heatpump is
entirely off. It's a 2014 Carrier "edge" thermostat.

Yes, you have posted about the limitations of your heatpump before. How is that relevant?

I suspect if you check with someone who knows, your backup heat will also run under two other conditions. One is the system detects ice on the outside coils. With a 40 degree cut off, your system might not worry with deicing. The other condition is when the system runs long enough that it decides the heat pump is not doing the job and switches to backup heat. Opps, another condition is if the inside temperature drops too far bellow the set temperature.

The first heat pump I owned was very, very simple. It had a two bulb thermostat. Set the temperature and bulb 1 would control the heat to keep the temperature. But if the room (hallway as the case may be) temperature dropped too far the second bulb switch would close and the backup heat would come on.

That is the condition I am trying to avoid with a thermostat which ramps the temperature up slowly enough to not kick in the backup heat.

I don't know of any heat pump that isn't set to work that way. Ask your installer. With the last system I bought I found I could not even get info from the company who made it. They always referred me to the "installer", like I was not worthy of information.


My thinking is, the thermostat sees a high delta between the house
temperature and the set temperature. In order to correct that (for your
comfort) it turns on both heat pump and auxiliary heat.

I suspect there is a wire from the thermostat to the control board,
that develops an output when there is a high delta, this output tells

the control board to turn on Auxiliary heat.

The truth may lie elsewhere, but that's my analysis.


On page 47 of the Thermostat manual, if this is the manual,
http://www.utcccs-cdn.com/hvac/docs/1009/Public/04/OM-TPPACA-01.pdf
It says,

"SPECIAL FEATURES Hybrid Heat (heat pump with a furnace system
only)This thermostat works with the Carrier Hybrid Heat systems
offering maximum comfort and economy by automatically controlling
whether your system delivers heating with the heat pump, with the
furnace, or with both options working together."


Page 52
Hybrid Heat (heat pump with a furnace system only)page 47........This
Carrier heating and cooling system concept offers maximum
comfort and economy. When a Hybrid Heat system is installed,
the thermostat automatically controls whether your system delivers
heating with the heat pump, with the furnace,or with both options
working together.
Mikek

Doesn't say anything about electric back up vs. oil, etc...

One very good reason to not run the heat pump with the backup electric heat is the power required.

Why are you arguing that. I understand why you are trying to shut down
the auxiliary heat.

I'm saying the thermostat might not run both heats at the same time if the back up is electric because it would be a very large load at one time, 15 kW.

They have separate breakers, but the electric coils in my house are 10
kW or 40 amps requiring a 50 amp circuit. The outside unit would
require a 30 amp breaker. Just how much can you wire into a panel
before it becomes a problem? If the kitchen were drawing 5 kW or more,
the hot water heater was running at 10 kW (or more) and the dryer was
running at 8 kW, that's pretty durn close to the house hold max. Throw
in an iron fire up the microwave and a few light bulbs and the main
breaker might blow. One of my other houses, only having 100 amp
service, might have blown the main breaker before the dryer was turned
on, but for the fact it has oil backup.

Not helpful info.

So, do you think or can you find out, if the Thermostat has a separate
output when the thermostat has a high differential to fire up the oil
furnace?
Mikek

I took the thermostat off the mount and took some photos. Maybe I can dig up a manual. I have no other way of knowing what the thermostat will do, but I can assure you that there is not a special output for "high differential temperature". There is a signal to turn on the heat pump and a signal to run the electric coils. The furnace may or may not cut off the heat pump when the coils are on regardless of what the thermostat does.

I appreciate the help, but I'm not looking for someone to reverse engineer my heating system. Originally I was asking if anyone knew about a thermostat that would ramp up the temperature in a way that would not trigger the back up heat. If I have to roll my own thermostat I'm sure I can figure out what I need to know to make it work.

The connector has the standard labeling of thermostats. The model is TCONT802AS32DAA Trane. I found manuals for it but they don't offer a lot of insight. I think a lot of this stuff is cut and dried and hasn't changed in 50 years or more. So they don't tell you any of the standard assumptions in the manuals.

--

Rick C.

---+ Get 1,000 miles of free Supercharging
---+ Tesla referral code - https://ts.la/richard11209

 

[Winfield Hill]

Rick C wrote...

Just how much can you wire into a panel before it
becomes a problem?

The basic limitation of course is your incoming circuit
breaker rating, typically 200A at 230V CT, for several
decades now. If you run low on room for high-current
230V dual breakers, it's time to have your electrician
install a second panel. We had a full panel with two
30A, and one each 40A + 50A breakers. Our electrician
moved some single lines to a second panel, and powered
it from a new 60A dual breaker. Now we have some room
to grow. If I need to add an 11kW 50A breaker for my
plug-in Prius, he can move over a few more circuits.

If you're suffering with 100A service, get upgraded!


--
Thanks,
- Win

 

[Rick C]

On Monday, January 13, 2020 at 10:30:50 PM UTC-5, Winfield Hill wrote:

Rick C wrote...

Just how much can you wire into a panel before it
becomes a problem?

The basic limitation of course is your incoming circuit
breaker rating, typically 200A at 230V CT, for several
decades now. If you run low on room for high-current
230V dual breakers, it's time to have your electrician
install a second panel. We had a full panel with two
30A, and one each 40A + 50A breakers. Our electrician
moved some single lines to a second panel, and powered
it from a new 60A dual breaker. Now we have some room
to grow. If I need to add an 11kW 50A breaker for my
plug-in Prius, he can move over a few more circuits.

If you're suffering with 100A service, get upgraded!

You seem to misunderstand the problem. Even with 200 amp service it is much easier to run out of head room if your heat system is drawing 70 or 80 amps. On a cold night, a family using hot water, a stove, the clothes dryer and a hair blow dryer may well be over the limit! I'm pretty sure I went though that with numbers and all.

It is seldom a matter of panel capacity. It is more often about the service.

--

Rick C.

--+- Get 1,000 miles of free Supercharging
--+- Tesla referral code - https://ts.la/richard11209

 

[Whoey Louie]

On Monday, January 13, 2020 at 11:24:00 PM UTC-5, Rick C wrote:

On Monday, January 13, 2020 at 10:30:50 PM UTC-5, Winfield Hill wrote:
Rick C wrote...

Just how much can you wire into a panel before it
becomes a problem?

The basic limitation of course is your incoming circuit
breaker rating, typically 200A at 230V CT, for several
decades now. If you run low on room for high-current
230V dual breakers, it's time to have your electrician
install a second panel. We had a full panel with two
30A, and one each 40A + 50A breakers. Our electrician
moved some single lines to a second panel, and powered
it from a new 60A dual breaker. Now we have some room
to grow. If I need to add an 11kW 50A breaker for my
plug-in Prius, he can move over a few more circuits.

If you're suffering with 100A service, get upgraded!

You seem to misunderstand the problem. Even with 200 amp service it is much easier to run out of head room if your heat system is drawing 70 or 80 amps.
On a cold night, a family using hot water, a stove, the clothes dryer and a hair blow dryer may well be over the limit! I'm pretty sure I went though that with numbers and all.

It is seldom a matter of panel capacity. It is more often about the service.

--

Rick C.

That's why I have nat gas, avoid all those problems. Not that I think
it's actually a real problem with a 200A service, mind you. With the
heat pump/electric heat pulling 80A, it still leaves 120A for the rest
of the house, which would work for me. But if
you really insist of having a service sized to absolute worst case,
sized to turn on all ovens, water heaters, dryer, washing machine,
hot tubs, 6 hair dryers and the heat pump with elect aux at the same time,
then I guess you should have a larger service.

 

[amdx]

On 1/13/2020 4:28 PM, Rick C wrote:

On Monday, January 13, 2020 at 1:52:26 PM UTC-5, amdx wrote:
On 1/13/2020 12:08 PM, Rick C wrote:
On Monday, January 13, 2020 at 12:37:39 PM UTC-5, amdx wrote:
On 1/11/2020 11:03 AM, Rick C wrote:
On Saturday, January 11, 2020 at 8:49:50 AM UTC-5, Winfield Hill wrote:
Rick C wrote...

My heatpump runs anytime the temperature is above 40F
= 4.4C (this is adjustable). The thermostat calls for
"aux" heat (oil furnace) when the outside temperature
is below that. When aux heat runs, the heatpump is
entirely off. It's a 2014 Carrier "edge" thermostat.

Yes, you have posted about the limitations of your heatpump before. How is that relevant?

I suspect if you check with someone who knows, your backup heat will also run under two other conditions. One is the system detects ice on the outside coils. With a 40 degree cut off, your system might not worry with deicing. The other condition is when the system runs long enough that it decides the heat pump is not doing the job and switches to backup heat. Opps, another condition is if the inside temperature drops too far bellow the set temperature.

The first heat pump I owned was very, very simple. It had a two bulb thermostat. Set the temperature and bulb 1 would control the heat to keep the temperature. But if the room (hallway as the case may be) temperature dropped too far the second bulb switch would close and the backup heat would come on.

That is the condition I am trying to avoid with a thermostat which ramps the temperature up slowly enough to not kick in the backup heat.

I don't know of any heat pump that isn't set to work that way. Ask your installer. With the last system I bought I found I could not even get info from the company who made it. They always referred me to the "installer", like I was not worthy of information.


My thinking is, the thermostat sees a high delta between the house
temperature and the set temperature. In order to correct that (for your
comfort) it turns on both heat pump and auxiliary heat.

I suspect there is a wire from the thermostat to the control board,
that develops an output when there is a high delta, this output tells

the control board to turn on Auxiliary heat.

The truth may lie elsewhere, but that's my analysis.


On page 47 of the Thermostat manual, if this is the manual,
http://www.utcccs-cdn.com/hvac/docs/1009/Public/04/OM-TPPACA-01.pdf
It says,

"SPECIAL FEATURES Hybrid Heat (heat pump with a furnace system
only)This thermostat works with the Carrier Hybrid Heat systems
offering maximum comfort and economy by automatically controlling
whether your system delivers heating with the heat pump, with the
furnace, or with both options working together."


Page 52
Hybrid Heat (heat pump with a furnace system only)page 47........This
Carrier heating and cooling system concept offers maximum
comfort and economy. When a Hybrid Heat system is installed,
the thermostat automatically controls whether your system delivers
heating with the heat pump, with the furnace,or with both options
working together.
Mikek

Doesn't say anything about electric back up vs. oil, etc...

One very good reason to not run the heat pump with the backup electric heat is the power required.

Why are you arguing that. I understand why you are trying to shut down
the auxiliary heat.

I'm saying the thermostat might not run both heats at the same time if the back up is electric because it would be a very large load at one time, 15 kW.


They have separate breakers, but the electric coils in my house are 10
kW or 40 amps requiring a 50 amp circuit. The outside unit would
require a 30 amp breaker. Just how much can you wire into a panel
before it becomes a problem? If the kitchen were drawing 5 kW or more,
the hot water heater was running at 10 kW (or more) and the dryer was
running at 8 kW, that's pretty durn close to the house hold max. Throw
in an iron fire up the microwave and a few light bulbs and the main
breaker might blow. One of my other houses, only having 100 amp
service, might have blown the main breaker before the dryer was turned
on, but for the fact it has oil backup.

Not helpful info.

So, do you think or can you find out, if the Thermostat has a separate
output when the thermostat has a high differential to fire up the oil
furnace?
Mikek

I took the thermostat off the mount and took some photos. Maybe I can dig up a manual. I have no other way of knowing what the thermostat will do, but I can assure you that there is not a special output for "high differential temperature". There is a signal to turn on the heat pump and a signal to run the electric coils. The furnace may or may not cut off the heat pump when the coils are on regardless of what the thermostat does.

I appreciate the help, but I'm not looking for someone to reverse engineer my heating system. Originally I was asking if anyone knew about a thermostat that would ramp up the temperature in a way that would not trigger the back up heat.

What is triggering the backup heat?

Does it just come on when the Heat pump comes on?
Probably no, I think you said it only comes on with either a
long run of the heat pump, or if the system has been off a long time.
One or the other, could you define that better for me?

What would cause you to want the oil furnace to come on?

Can you you just put an on off switch in the oil furnace
turn on signal line?
That way, if you want oil heat just flip the switch.


If I have to roll my own thermostat I'm sure I can figure out what I
need to know to make it work.

The connector has the standard labeling of thermostats. The model is TCONT802AS32DAA Trane. I found manuals for it but they don't offer a lot of insight. I think a lot of this stuff is cut and dried and hasn't changed in 50 years or more. So they don't tell you any of the standard assumptions in the manuals.

Have you looked at this page?
https://www.manualslib.com/manual/461448/Trane-Tcont802as32da.html?page=18#manual

Does it apply to your thermostat setup?

I'm especially curious about #5.
#5. Choose appropriate Balance Point Temperature
in Installer Setup Number 0350.

There might be more info to glean from this thermostat setup page.

https://www.manualslib.com/manual/461448/Trane-Tcont802as32da.html?page=12#manual

Mikek

 

[Whoey Louie]

On Monday, January 13, 2020 at 5:28:41 PM UTC-5, Rick C wrote:

On Monday, January 13, 2020 at 1:52:26 PM UTC-5, amdx wrote:
On 1/13/2020 12:08 PM, Rick C wrote:
On Monday, January 13, 2020 at 12:37:39 PM UTC-5, amdx wrote:
On 1/11/2020 11:03 AM, Rick C wrote:
On Saturday, January 11, 2020 at 8:49:50 AM UTC-5, Winfield Hill wrote:
Rick C wrote...

My heatpump runs anytime the temperature is above 40F
= 4.4C (this is adjustable). The thermostat calls for
"aux" heat (oil furnace) when the outside temperature
is below that. When aux heat runs, the heatpump is
entirely off. It's a 2014 Carrier "edge" thermostat.

Yes, you have posted about the limitations of your heatpump before. How is that relevant?

I suspect if you check with someone who knows, your backup heat will also run under two other conditions. One is the system detects ice on the outside coils. With a 40 degree cut off, your system might not worry with deicing. The other condition is when the system runs long enough that it decides the heat pump is not doing the job and switches to backup heat. Opps, another condition is if the inside temperature drops too far bellow the set temperature.

The first heat pump I owned was very, very simple. It had a two bulb thermostat. Set the temperature and bulb 1 would control the heat to keep the temperature. But if the room (hallway as the case may be) temperature dropped too far the second bulb switch would close and the backup heat would come on.

That is the condition I am trying to avoid with a thermostat which ramps the temperature up slowly enough to not kick in the backup heat.

I don't know of any heat pump that isn't set to work that way. Ask your installer. With the last system I bought I found I could not even get info from the company who made it. They always referred me to the "installer", like I was not worthy of information.


My thinking is, the thermostat sees a high delta between the house
temperature and the set temperature. In order to correct that (for your
comfort) it turns on both heat pump and auxiliary heat.

I suspect there is a wire from the thermostat to the control board,
that develops an output when there is a high delta, this output tells

the control board to turn on Auxiliary heat.

The truth may lie elsewhere, but that's my analysis.


On page 47 of the Thermostat manual, if this is the manual,
http://www.utcccs-cdn.com/hvac/docs/1009/Public/04/OM-TPPACA-01.pdf
It says,

"SPECIAL FEATURES Hybrid Heat (heat pump with a furnace system
only)This thermostat works with the Carrier Hybrid Heat systems
offering maximum comfort and economy by automatically controlling
whether your system delivers heating with the heat pump, with the
furnace, or with both options working together."


Page 52
Hybrid Heat (heat pump with a furnace system only)page 47........This
Carrier heating and cooling system concept offers maximum
comfort and economy. When a Hybrid Heat system is installed,
the thermostat automatically controls whether your system delivers
heating with the heat pump, with the furnace,or with both options
working together.
Mikek

Doesn't say anything about electric back up vs. oil, etc...

One very good reason to not run the heat pump with the backup electric heat is the power required.

Why are you arguing that. I understand why you are trying to shut down
the auxiliary heat.

I'm saying the thermostat might not run both heats at the same time if the back up is electric because it would be a very large load at one time, 15 kW.

Might be this, might be that. RTFM.

They have separate breakers, but the electric coils in my house are 10
kW or 40 amps requiring a 50 amp circuit. The outside unit would
require a 30 amp breaker. Just how much can you wire into a panel
before it becomes a problem? If the kitchen were drawing 5 kW or more,
the hot water heater was running at 10 kW (or more) and the dryer was
running at 8 kW, that's pretty durn close to the house hold max. Throw
in an iron fire up the microwave and a few light bulbs and the main
breaker might blow. One of my other houses, only having 100 amp
service, might have blown the main breaker before the dryer was turned
on, but for the fact it has oil backup.

Not helpful info.

So, do you think or can you find out, if the Thermostat has a separate
output when the thermostat has a high differential to fire up the oil
furnace?
Mikek

I took the thermostat off the mount and took some photos. Maybe I can dig up a manual.

Duh! I would have done that first.




I have no other way of knowing what the thermostat will do, but I can assure you that there is not a special output for "high differential temperature". There is a signal to turn on the heat pump and a signal to run the electric coils. The furnace may or may not cut off the heat pump when the coils are on regardless of what the thermostat does.

I appreciate the help, but I'm not looking for someone to reverse engineer my heating system. Originally I was asking if anyone knew about a thermostat that would ramp up the temperature in a way that would not trigger the back up heat.

Go figure. Instead of reading the manual for the thermostat you already
have to see what it does, what can be changed by programming, you want
to look for a new one.




If I have to roll my own thermostat I'm sure I can figure out what I need to know to make it work.

The connector has the standard labeling of thermostats. The model is TCONT802AS32DAA Trane. I found manuals for it but they don't offer a lot of insight. I think a lot of this stuff is cut and dried and hasn't changed in 50 years or more. So they don't tell you any of the standard assumptions in the manuals.

That looks like the Honeywell VisionPro series. The VP series doesn't
have a setting for what you want, so the Trane one probably does not either..

--

Rick C.

---+ Get 1,000 miles of free Supercharging
---+ Tesla referral code - https://ts.la/richard11209

 

[Whoey Louie]

On Monday, January 13, 2020 at 1:08:19 PM UTC-5, Rick C wrote:

On Monday, January 13, 2020 at 12:37:39 PM UTC-5, amdx wrote:
On 1/11/2020 11:03 AM, Rick C wrote:
On Saturday, January 11, 2020 at 8:49:50 AM UTC-5, Winfield Hill wrote:
Rick C wrote...

My heatpump runs anytime the temperature is above 40F
= 4.4C (this is adjustable). The thermostat calls for
"aux" heat (oil furnace) when the outside temperature
is below that. When aux heat runs, the heatpump is
entirely off. It's a 2014 Carrier "edge" thermostat.

Yes, you have posted about the limitations of your heatpump before. How is that relevant?

I suspect if you check with someone who knows, your backup heat will also run under two other conditions. One is the system detects ice on the outside coils. With a 40 degree cut off, your system might not worry with deicing. The other condition is when the system runs long enough that it decides the heat pump is not doing the job and switches to backup heat. Opps, another condition is if the inside temperature drops too far bellow the set temperature.

The first heat pump I owned was very, very simple. It had a two bulb thermostat. Set the temperature and bulb 1 would control the heat to keep the temperature. But if the room (hallway as the case may be) temperature dropped too far the second bulb switch would close and the backup heat would come on.

That is the condition I am trying to avoid with a thermostat which ramps the temperature up slowly enough to not kick in the backup heat.

I don't know of any heat pump that isn't set to work that way. Ask your installer. With the last system I bought I found I could not even get info from the company who made it. They always referred me to the "installer", like I was not worthy of information.


My thinking is, the thermostat sees a high delta between the house
temperature and the set temperature. In order to correct that (for your
comfort) it turns on both heat pump and auxiliary heat.

I suspect there is a wire from the thermostat to the control board,
that develops an output when there is a high delta, this output tells

the control board to turn on Auxiliary heat.

The truth may lie elsewhere, but that's my analysis.


On page 47 of the Thermostat manual, if this is the manual,
http://www.utcccs-cdn.com/hvac/docs/1009/Public/04/OM-TPPACA-01.pdf
It says,

"SPECIAL FEATURES Hybrid Heat (heat pump with a furnace system
only)This thermostat works with the Carrier Hybrid Heat systems
offering maximum comfort and economy by automatically controlling
whether your system delivers heating with the heat pump, with the
furnace, or with both options working together."


Page 52
Hybrid Heat (heat pump with a furnace system only)page 47........This
Carrier heating and cooling system concept offers maximum
comfort and economy. When a Hybrid Heat system is installed,
the thermostat automatically controls whether your system delivers
heating with the heat pump, with the furnace,or with both options
working together.
Mikek

Doesn't say anything about electric back up vs. oil, etc...

One very good reason to not run the heat pump with the backup electric heat is the power required. They have separate breakers, but the electric coils in my house are 10 kW or 40 amps requiring a 50 amp circuit. The outside unit would require a 30 amp breaker.

The breaker is sized significantly higher than the operating load to
handle the brief start-up current. It's probably pulling more like 15 or 20
once running.




> Just how much can you wire into a panel before it becomes a problem?

That depends on the service capacity.

 

[Whoey Louie]

On Tuesday, January 14, 2020 at 10:24:22 AM UTC-5, amdx wrote:

On 1/13/2020 4:28 PM, Rick C wrote:
On Monday, January 13, 2020 at 1:52:26 PM UTC-5, amdx wrote:
On 1/13/2020 12:08 PM, Rick C wrote:
On Monday, January 13, 2020 at 12:37:39 PM UTC-5, amdx wrote:
On 1/11/2020 11:03 AM, Rick C wrote:
On Saturday, January 11, 2020 at 8:49:50 AM UTC-5, Winfield Hill wrote:
Rick C wrote...

My heatpump runs anytime the temperature is above 40F
= 4.4C (this is adjustable). The thermostat calls for
"aux" heat (oil furnace) when the outside temperature
is below that. When aux heat runs, the heatpump is
entirely off. It's a 2014 Carrier "edge" thermostat.

Yes, you have posted about the limitations of your heatpump before. How is that relevant?

I suspect if you check with someone who knows, your backup heat will also run under two other conditions. One is the system detects ice on the outside coils. With a 40 degree cut off, your system might not worry with deicing. The other condition is when the system runs long enough that it decides the heat pump is not doing the job and switches to backup heat. Opps, another condition is if the inside temperature drops too far bellow the set temperature.

The first heat pump I owned was very, very simple. It had a two bulb thermostat. Set the temperature and bulb 1 would control the heat to keep the temperature. But if the room (hallway as the case may be) temperature dropped too far the second bulb switch would close and the backup heat would come on.

That is the condition I am trying to avoid with a thermostat which ramps the temperature up slowly enough to not kick in the backup heat.

I don't know of any heat pump that isn't set to work that way. Ask your installer. With the last system I bought I found I could not even get info from the company who made it. They always referred me to the "installer", like I was not worthy of information.


My thinking is, the thermostat sees a high delta between the house
temperature and the set temperature. In order to correct that (for your
comfort) it turns on both heat pump and auxiliary heat.

I suspect there is a wire from the thermostat to the control board,
that develops an output when there is a high delta, this output tells

the control board to turn on Auxiliary heat.

The truth may lie elsewhere, but that's my analysis.


On page 47 of the Thermostat manual, if this is the manual,
http://www.utcccs-cdn.com/hvac/docs/1009/Public/04/OM-TPPACA-01.pdf
It says,

"SPECIAL FEATURES Hybrid Heat (heat pump with a furnace system
only)This thermostat works with the Carrier Hybrid Heat systems
offering maximum comfort and economy by automatically controlling
whether your system delivers heating with the heat pump, with the
furnace, or with both options working together."


Page 52
Hybrid Heat (heat pump with a furnace system only)page 47........This
Carrier heating and cooling system concept offers maximum
comfort and economy. When a Hybrid Heat system is installed,
the thermostat automatically controls whether your system delivers
heating with the heat pump, with the furnace,or with both options
working together.
Mikek

Doesn't say anything about electric back up vs. oil, etc...

One very good reason to not run the heat pump with the backup electric heat is the power required.

Why are you arguing that. I understand why you are trying to shut down
the auxiliary heat.

I'm saying the thermostat might not run both heats at the same time if the back up is electric because it would be a very large load at one time, 15 kW.


They have separate breakers, but the electric coils in my house are 10
kW or 40 amps requiring a 50 amp circuit. The outside unit would
require a 30 amp breaker. Just how much can you wire into a panel
before it becomes a problem? If the kitchen were drawing 5 kW or more,
the hot water heater was running at 10 kW (or more) and the dryer was
running at 8 kW, that's pretty durn close to the house hold max. Throw
in an iron fire up the microwave and a few light bulbs and the main
breaker might blow. One of my other houses, only having 100 amp
service, might have blown the main breaker before the dryer was turned
on, but for the fact it has oil backup.

Not helpful info.

So, do you think or can you find out, if the Thermostat has a separate
output when the thermostat has a high differential to fire up the oil
furnace?
Mikek

I took the thermostat off the mount and took some photos. Maybe I can dig up a manual. I have no other way of knowing what the thermostat will do, but I can assure you that there is not a special output for "high differential temperature". There is a signal to turn on the heat pump and a signal to run the electric coils. The furnace may or may not cut off the heat pump when the coils are on regardless of what the thermostat does.

I appreciate the help, but I'm not looking for someone to reverse engineer my heating system. Originally I was asking if anyone knew about a thermostat that would ramp up the temperature in a way that would not trigger the back up heat.

What is triggering the backup heat?

In the typical install, the thermostat makes the call, because it has the
best information, ie what the set temp is, what the actual is, how long
it's been running already. The Trane thermostat he has looks just like
the Honeywell Vision Pro series and that's how they work. He also says
that the thermostat has a wire for aux heat, that settles it for me.

Does it just come on when the Heat pump comes on?
Probably no, I think you said it only comes on with either a
long run of the heat pump, or if the system has been off a long time.
One or the other, could you define that better for me?

It has gotten confusing. I thought he was saying that the aux heat
only comes on when it's needed, to supplement the heat pump. Now he's
saying that it may shut off the heat pump when it comes on, which
makes no sense to me. You'd think he'd know how it behaves.

What would cause you to want the oil furnace to come on?

Maybe I'm confused here, but I thought the system he's talking about
is a heat pump with aux electric heat. I think the oil furnace was
a previous house. And he doesn't want the aux heat to come on during
certain periods, when electric rate is high, that's the whole point.
Here are two scenarios where that happens:

1 - You leave the house during the day for 8 hours, set the temp back
to save energy. Now either you come home or it's programmed to get back
to normal temp at say 5PM. So, now the temp is 65, the desired is 70.
The thermostat sees that and invokes aux heat to get it there as fast
as possible. If you are there, you could get around that by raising
it maybe 2 deg at a time, but then that's a pain too.

2 - Same as 1, but setback over night. The fact that heat pumps can
take a long time to recover and this issue leads many to not set them
back overnight.

Can you you just put an on off switch in the oil furnace
turn on signal line?
That way, if you want oil heat just flip the switch.

He could do that, but then he has to remember to work the switch
and it's not exactly desirable. Like I've said a couple times now,
an obvious solution is for these thermostats to have an option where
it estimates how long it will take to reach the set temp and then
only invokes aux heat if it will be longer than X minutes, where X
is user programmable. That kind of does it. A further refinement
would be to factor in time of day. Like you may be willing to live
with a 3 hour ramp during the day when you're not likely to be
there, but not at 7AM when you're getting up.

If I have to roll my own thermostat I'm sure I can figure out what I
need to know to make it work.

The connector has the standard labeling of thermostats. The model is TCONT802AS32DAA Trane. I found manuals for it but they don't offer a lot of insight. I think a lot of this stuff is cut and dried and hasn't changed in 50 years or more. So they don't tell you any of the standard assumptions in the manuals.

Have you looked at this page?
https://www.manualslib.com/manual/461448/Trane-Tcont802as32da.html?page=18#manual


Does it apply to your thermostat setup?

I'm especially curious about #5.
#5. Choose appropriate Balance Point Temperature
in Installer Setup Number 0350.

The balance point affects the swing between on and off. I don't see
it solving his issue.

There might be more info to glean from this thermostat setup page.
https://www.manualslib.com/manual/461448/Trane-Tcont802as32da.html?page=12#manual


Mikek

 

[amdx]

On 1/14/2020 9:47 AM, Whoey Louie wrote:

On Tuesday, January 14, 2020 at 10:24:22 AM UTC-5, amdx wrote:
On 1/13/2020 4:28 PM, Rick C wrote:
On Monday, January 13, 2020 at 1:52:26 PM UTC-5, amdx wrote:
On 1/13/2020 12:08 PM, Rick C wrote:
On Monday, January 13, 2020 at 12:37:39 PM UTC-5, amdx wrote:
On 1/11/2020 11:03 AM, Rick C wrote:
On Saturday, January 11, 2020 at 8:49:50 AM UTC-5, Winfield Hill wrote:
Rick C wrote...

My heatpump runs anytime the temperature is above 40F
= 4.4C (this is adjustable). The thermostat calls for
"aux" heat (oil furnace) when the outside temperature
is below that. When aux heat runs, the heatpump is
entirely off. It's a 2014 Carrier "edge" thermostat.

Yes, you have posted about the limitations of your heatpump before. How is that relevant?

I suspect if you check with someone who knows, your backup heat will also run under two other conditions. One is the system detects ice on the outside coils. With a 40 degree cut off, your system might not worry with deicing. The other condition is when the system runs long enough that it decides the heat pump is not doing the job and switches to backup heat. Opps, another condition is if the inside temperature drops too far bellow the set temperature.

The first heat pump I owned was very, very simple. It had a two bulb thermostat. Set the temperature and bulb 1 would control the heat to keep the temperature. But if the room (hallway as the case may be) temperature dropped too far the second bulb switch would close and the backup heat would come on.

That is the condition I am trying to avoid with a thermostat which ramps the temperature up slowly enough to not kick in the backup heat.

I don't know of any heat pump that isn't set to work that way. Ask your installer. With the last system I bought I found I could not even get info from the company who made it. They always referred me to the "installer", like I was not worthy of information.


My thinking is, the thermostat sees a high delta between the house
temperature and the set temperature. In order to correct that (for your
comfort) it turns on both heat pump and auxiliary heat.

I suspect there is a wire from the thermostat to the control board,
that develops an output when there is a high delta, this output tells

the control board to turn on Auxiliary heat.

The truth may lie elsewhere, but that's my analysis.


On page 47 of the Thermostat manual, if this is the manual,
http://www.utcccs-cdn.com/hvac/docs/1009/Public/04/OM-TPPACA-01.pdf
It says,

"SPECIAL FEATURES Hybrid Heat (heat pump with a furnace system
only)This thermostat works with the Carrier Hybrid Heat systems
offering maximum comfort and economy by automatically controlling
whether your system delivers heating with the heat pump, with the
furnace, or with both options working together."


Page 52
Hybrid Heat (heat pump with a furnace system only)page 47........This
Carrier heating and cooling system concept offers maximum
comfort and economy. When a Hybrid Heat system is installed,
the thermostat automatically controls whether your system delivers
heating with the heat pump, with the furnace,or with both options
working together.
Mikek

Doesn't say anything about electric back up vs. oil, etc...

One very good reason to not run the heat pump with the backup electric heat is the power required.

Why are you arguing that. I understand why you are trying to shut down
the auxiliary heat.

I'm saying the thermostat might not run both heats at the same time if the back up is electric because it would be a very large load at one time, 15 kW.


They have separate breakers, but the electric coils in my house are 10
kW or 40 amps requiring a 50 amp circuit. The outside unit would
require a 30 amp breaker. Just how much can you wire into a panel
before it becomes a problem? If the kitchen were drawing 5 kW or more,
the hot water heater was running at 10 kW (or more) and the dryer was
running at 8 kW, that's pretty durn close to the house hold max. Throw
in an iron fire up the microwave and a few light bulbs and the main
breaker might blow. One of my other houses, only having 100 amp
service, might have blown the main breaker before the dryer was turned
on, but for the fact it has oil backup.

Not helpful info.

So, do you think or can you find out, if the Thermostat has a separate
output when the thermostat has a high differential to fire up the oil
furnace?
Mikek

I took the thermostat off the mount and took some photos. Maybe I can dig up a manual. I have no other way of knowing what the thermostat will do, but I can assure you that there is not a special output for "high differential temperature". There is a signal to turn on the heat pump and a signal to run the electric coils. The furnace may or may not cut off the heat pump when the coils are on regardless of what the thermostat does.

I appreciate the help, but I'm not looking for someone to reverse engineer my heating system. Originally I was asking if anyone knew about a thermostat that would ramp up the temperature in a way that would not trigger the back up heat.

What is triggering the backup heat?

In the typical install, the thermostat makes the call, because it has the
best information, ie what the set temp is, what the actual is, how long
it's been running already. The Trane thermostat he has looks just like
the Honeywell Vision Pro series and that's how they work. He also says
that the thermostat has a wire for aux heat, that settles it for me.

Yes, it would seem to me that the thermostat would have a separate
wire going to the control board for Aux heat.
And that's what turns on the aux, weather it's electric or oil.

Does it just come on when the Heat pump comes on?
Probably no, I think you said it only comes on with either a
long run of the heat pump, or if the system has been off a long time.
One or the other, could you define that better for me?

It has gotten confusing. I thought he was saying that the aux heat
only comes on when it's needed, to supplement the heat pump.

Then the question is, How does the thermostat determine, "when it's needed".
It might help if he listed the setting install on the page,

https://www.manualslib.com/manual/461448/Trane-Tcont802as32da.html?page=12#manual
starting with Setup Number O170.

Now he's

saying that it may shut off the heat pump when it comes on, which
makes no sense to me. You'd think he'd know how it behaves.

Maybe he needs to start fresh. I was hoping I get answers to each
question I ask and that would help pin point what's going on, hasn't
happened yet.

What would cause you to want the oil furnace to come on?

Maybe I'm confused here, but I thought the system he's talking about
is a heat pump with aux electric heat. I think the oil furnace was
a previous house. And he doesn't want the aux heat to come on during
certain periods, when electric rate is high, that's the whole point.
Here are two scenarios where that happens:

1 - You leave the house during the day for 8 hours, set the temp back
to save energy. Now either you come home or it's programmed to get back
to normal temp at say 5PM. So, now the temp is 65, the desired is 70.
The thermostat sees that and invokes aux heat to get it there as fast
as possible. If you are there, you could get around that by raising
it maybe 2 deg at a time, but then that's a pain too.

2 - Same as 1, but setback over night. The fact that heat pumps can
take a long time to recover and this issue leads many to not set them
back overnight.






Can you you just put an on off switch in the oil furnace
turn on signal line?
That way, if you want oil heat just flip the switch.

He could do that, but then he has to remember to work the switch
and it's not exactly desirable. Like I've said a couple times now,
an obvious solution is for these thermostats to have an option where
it estimates how long it will take to reach the set temp and then
only invokes aux heat if it will be longer than X minutes, where X
is user programmable. That kind of does it. A further refinement
would be to factor in time of day. Like you may be willing to live
with a 3 hour ramp during the day when you're not likely to be
there, but not at 7AM when you're getting up.





If I have to roll my own thermostat I'm sure I can figure out what I
need to know to make it work.

The connector has the standard labeling of thermostats. The model is TCONT802AS32DAA Trane. I found manuals for it but they don't offer a lot of insight. I think a lot of this stuff is cut and dried and hasn't changed in 50 years or more. So they don't tell you any of the standard assumptions in the manuals.

Have you looked at this page?
https://www.manualslib.com/manual/461448/Trane-Tcont802as32da.html?page=18#manual


Does it apply to your thermostat setup?

I'm especially curious about #5.
#5. Choose appropriate Balance Point Temperature
in Installer Setup Number 0350.

The balance point affects the swing between on and off. I don't see
it solving his issue.





There might be more info to glean from this thermostat setup page.
https://www.manualslib.com/manual/461448/Trane-Tcont802as32da.html?page=12#manual


Mikek

 

[Whoey Louie]

On Tuesday, January 14, 2020 at 12:41:14 PM UTC-5, amdx wrote:

On 1/14/2020 9:47 AM, Whoey Louie wrote:
On Tuesday, January 14, 2020 at 10:24:22 AM UTC-5, amdx wrote:
On 1/13/2020 4:28 PM, Rick C wrote:
On Monday, January 13, 2020 at 1:52:26 PM UTC-5, amdx wrote:
On 1/13/2020 12:08 PM, Rick C wrote:
On Monday, January 13, 2020 at 12:37:39 PM UTC-5, amdx wrote:
On 1/11/2020 11:03 AM, Rick C wrote:
On Saturday, January 11, 2020 at 8:49:50 AM UTC-5, Winfield Hill wrote:
Rick C wrote...

My heatpump runs anytime the temperature is above 40F
= 4.4C (this is adjustable). The thermostat calls for
"aux" heat (oil furnace) when the outside temperature
is below that. When aux heat runs, the heatpump is
entirely off. It's a 2014 Carrier "edge" thermostat.

Yes, you have posted about the limitations of your heatpump before. How is that relevant?

I suspect if you check with someone who knows, your backup heat will also run under two other conditions. One is the system detects ice on the outside coils. With a 40 degree cut off, your system might not worry with deicing. The other condition is when the system runs long enough that it decides the heat pump is not doing the job and switches to backup heat. Opps, another condition is if the inside temperature drops too far bellow the set temperature.

The first heat pump I owned was very, very simple. It had a two bulb thermostat. Set the temperature and bulb 1 would control the heat to keep the temperature. But if the room (hallway as the case may be) temperature dropped too far the second bulb switch would close and the backup heat would come on.

That is the condition I am trying to avoid with a thermostat which ramps the temperature up slowly enough to not kick in the backup heat.

I don't know of any heat pump that isn't set to work that way. Ask your installer. With the last system I bought I found I could not even get info from the company who made it. They always referred me to the "installer", like I was not worthy of information.


My thinking is, the thermostat sees a high delta between the house
temperature and the set temperature. In order to correct that (for your
comfort) it turns on both heat pump and auxiliary heat.

I suspect there is a wire from the thermostat to the control board,
that develops an output when there is a high delta, this output tells

the control board to turn on Auxiliary heat.

The truth may lie elsewhere, but that's my analysis.


On page 47 of the Thermostat manual, if this is the manual,
http://www.utcccs-cdn.com/hvac/docs/1009/Public/04/OM-TPPACA-01.pdf
It says,

"SPECIAL FEATURES Hybrid Heat (heat pump with a furnace system
only)This thermostat works with the Carrier Hybrid Heat systems
offering maximum comfort and economy by automatically controlling
whether your system delivers heating with the heat pump, with the
furnace, or with both options working together."


Page 52
Hybrid Heat (heat pump with a furnace system only)page 47........This
Carrier heating and cooling system concept offers maximum
comfort and economy. When a Hybrid Heat system is installed,
the thermostat automatically controls whether your system delivers
heating with the heat pump, with the furnace,or with both options
working together.
Mikek

Doesn't say anything about electric back up vs. oil, etc...

One very good reason to not run the heat pump with the backup electric heat is the power required.

Why are you arguing that. I understand why you are trying to shut down
the auxiliary heat.

I'm saying the thermostat might not run both heats at the same time if the back up is electric because it would be a very large load at one time, 15 kW.


They have separate breakers, but the electric coils in my house are 10
kW or 40 amps requiring a 50 amp circuit. The outside unit would
require a 30 amp breaker. Just how much can you wire into a panel
before it becomes a problem? If the kitchen were drawing 5 kW or more,
the hot water heater was running at 10 kW (or more) and the dryer was
running at 8 kW, that's pretty durn close to the house hold max. Throw
in an iron fire up the microwave and a few light bulbs and the main
breaker might blow. One of my other houses, only having 100 amp
service, might have blown the main breaker before the dryer was turned
on, but for the fact it has oil backup.

Not helpful info.

So, do you think or can you find out, if the Thermostat has a separate
output when the thermostat has a high differential to fire up the oil
furnace?
Mikek

I took the thermostat off the mount and took some photos. Maybe I can dig up a manual. I have no other way of knowing what the thermostat will do, but I can assure you that there is not a special output for "high differential temperature". There is a signal to turn on the heat pump and a signal to run the electric coils. The furnace may or may not cut off the heat pump when the coils are on regardless of what the thermostat does.

I appreciate the help, but I'm not looking for someone to reverse engineer my heating system. Originally I was asking if anyone knew about a thermostat that would ramp up the temperature in a way that would not trigger the back up heat.

What is triggering the backup heat?

In the typical install, the thermostat makes the call, because it has the
best information, ie what the set temp is, what the actual is, how long
it's been running already. The Trane thermostat he has looks just like
the Honeywell Vision Pro series and that's how they work. He also says
that the thermostat has a wire for aux heat, that settles it for me.



Yes, it would seem to me that the thermostat would have a separate
wire going to the control board for Aux heat.
And that's what turns on the aux, weather it's electric or oil.





Does it just come on when the Heat pump comes on?
Probably no, I think you said it only comes on with either a
long run of the heat pump, or if the system has been off a long time.
One or the other, could you define that better for me?

It has gotten confusing. I thought he was saying that the aux heat
only comes on when it's needed, to supplement the heat pump.

Then the question is, How does the thermostat determine, "when it's needed".

I think they typically base it on how big the temp delta that it has to
close is. If it's one or two deg and the system has not been running
a lot just to maintain, then it uses heat pump only. If it's more
than about 2 deg or it's been running most of the time just to maintain
the temp, then it uses both.

It might help if he listed the setting install on the page,
https://www.manualslib.com/manual/461448/Trane-Tcont802as32da.html?page=12#manual
starting with Setup Number O170.

Like I said, that thermostat is surely made by Honeywell, it looks
just like the VisionPro Series. I have one, I looked at it's settings
and there is nothing there to control aux heat, with two exceptions

1 - You can enable or disable it

2 - If you have an optional external temp sensor, you can disable it
above 40 to 60F, where you get to set that temperature. The idea being
if it's say 50F outside, you know it works well enough that it can heat
without aux heat and you're willing to wait. I pointed that out before,
it would be a partial solution to disable aux heat some of the time,
if he sets it to 40F, at least it would not come on part of the time.
But maybe that is actually a solution for most of the time. When it's
below 40F out it may take so long to get the temp up with just the heat
pump that you'd want aux on anyway.
But hooking up an outside sensor could be a big issue and his thermostat
may not support it. You'd think some thermostats would have more prog
control over when it comes on, like at least how big the temp delta
has to be.

 

[amdx]

On 1/11/2020 1:42 PM, Rick C wrote:

On Saturday, January 11, 2020 at 2:22:08 PM UTC-5, Whoey Louie wrote:
On Saturday, January 11, 2020 at 12:07:33 PM UTC-5, Rick C wrote:
On Saturday, January 11, 2020 at 11:12:33 AM UTC-5, Whoey Louie wrote:
On Friday, January 10, 2020 at 10:54:48 PM UTC-5, Rick C wrote:
I am using a programmable thermostat to turn off the heat and/or air conditioning during the peak usage times as set by the ToU billing with my utility. The problem I have is the heat pump not ramping up the temperature fast enough when it comes back on and the backup straight electric heat coming on. This uses maybe three times the amount of electricity during the time it takes to get up to temperature.

I don't know if this is caused by the thermostat or the heat pump itself. I'm wondering if anyone makes a programmable thermostat that deals with this issue. If the problem is caused by the thermostat not letting the heat pump run long enough that is easy to fix. If the problem is caused by the heat pump itself, then the way to deal with it is for the thermostat to run the heat pump in bursts short enough to keep the back up heat from running.

Anyone familiar with this? Consumer Reports doesn't mention this in a quick look at a few thermostats. The do list "Early recovery" which turns on the heat/cooling ahead of the set time so the home is at the right temperature when you arrive (rather pointless in my opinion since I can just set the time early if that is what I wanted.)

They are starting to address the ToU billing issue in EV charging. Any sign of this in home heating/cooling?

--

Rick C.

- Get 1,000 miles of free Supercharging
- Tesla referral code - https://ts.la/richard11209

Honeywell VisionPro Series has adaptive recovery. You set the time and
temp for what you want it to actually be and for recovery after setback
it then figures out what time to fire it up to get it there. And it learns.

That is exactly wrong for my situation. I mentioned that in my first post. Another company calls it "Early recovery".


It works excellent with the gas furnace here and it supports heat pumps,
so I would expect it will work the same with those. IDK what algorithm
they use, but obviously it's based on how big the delta is that it has
to close and how fast the thermostat knows it takes to raise the temp one
degree. Besides that, I would think it may factor in how fast the temp
has dropped while in setback, to get some gauge as to how cold it is
outside, to further refine the calculation. It always makes it to the
desired temp by the desired time.

Yeah, that sounds like it works well, but it's a great solution to the wrong problem.


OK, you're right. But it's a similar problem, a very common problem
and I would think you would have that too.

Not trying to be rude, but if you think I have both problems, then you don't understand the problem I am having.

I want the heat to be OFF during the peak times of my ToU rates. Not reduced, not cut back, OFF.

I can do that by programming the thermostat low enough that the heat never comes on. But when the peak time is over, the temperature setting is restored to the intended setting and the heat comes on.

After some time the back up heat comes on and the electric meter spins
like a top.

After some time? How much time, is it the exact same amount of time
every time? IF yes, then I must be a signal from the Thermostat or on
the control board to turn on the aux heat.

I see this, here,

https://www.manualslib.com/manual/461448/Trane-Tcont802as32da.html?page=18#manual

OPERATION IN HEAT MODE
When the outdoor temperature is below the Compressor
Lockout Temperature, only the Auxiliary Heat operates.

When the outdoor temperature is above the Auxiliary
Lockout Temperature, only the Compressor operates.

See Fig. 21.
COMPRESSOR ONLY
Above 50*
--------------------------------
BOTH COMPRESSOR AND
AUXILIARY HEAT
Above 35* and below 50*
--------------------------------------
AUXILIARY ONLY
Fig. 21. Heat Pump Operation with Lockout
Temperatures Set.
Below 35*

When the outdoor temperature is between the two
temperatures, both the Compressor and Auxiliary Heat
operate

Can you check to see if you have the outside temperature sensor?
It will connect to S1 and W1 in your thermostat and be a separate
pair from outside to the thermostat.

Mikek

 

[amdx]

On 1/14/2020 12:11 PM, Whoey Louie wrote:

On Tuesday, January 14, 2020 at 12:41:14 PM UTC-5, amdx wrote:
On 1/14/2020 9:47 AM, Whoey Louie wrote:
On Tuesday, January 14, 2020 at 10:24:22 AM UTC-5, amdx wrote:
On 1/13/2020 4:28 PM, Rick C wrote:
On Monday, January 13, 2020 at 1:52:26 PM UTC-5, amdx wrote:
On 1/13/2020 12:08 PM, Rick C wrote:
On Monday, January 13, 2020 at 12:37:39 PM UTC-5, amdx wrote:
On 1/11/2020 11:03 AM, Rick C wrote:
On Saturday, January 11, 2020 at 8:49:50 AM UTC-5, Winfield Hill wrote:
Rick C wrote...

My heatpump runs anytime the temperature is above 40F
= 4.4C (this is adjustable). The thermostat calls for
"aux" heat (oil furnace) when the outside temperature
is below that. When aux heat runs, the heatpump is
entirely off. It's a 2014 Carrier "edge" thermostat.

Yes, you have posted about the limitations of your heatpump before. How is that relevant?

I suspect if you check with someone who knows, your backup heat will also run under two other conditions. One is the system detects ice on the outside coils. With a 40 degree cut off, your system might not worry with deicing. The other condition is when the system runs long enough that it decides the heat pump is not doing the job and switches to backup heat. Opps, another condition is if the inside temperature drops too far bellow the set temperature.

The first heat pump I owned was very, very simple. It had a two bulb thermostat. Set the temperature and bulb 1 would control the heat to keep the temperature. But if the room (hallway as the case may be) temperature dropped too far the second bulb switch would close and the backup heat would come on.

That is the condition I am trying to avoid with a thermostat which ramps the temperature up slowly enough to not kick in the backup heat.

I don't know of any heat pump that isn't set to work that way. Ask your installer. With the last system I bought I found I could not even get info from the company who made it. They always referred me to the "installer", like I was not worthy of information.


My thinking is, the thermostat sees a high delta between the house
temperature and the set temperature. In order to correct that (for your
comfort) it turns on both heat pump and auxiliary heat.

I suspect there is a wire from the thermostat to the control board,
that develops an output when there is a high delta, this output tells

the control board to turn on Auxiliary heat.

The truth may lie elsewhere, but that's my analysis.


On page 47 of the Thermostat manual, if this is the manual,
http://www.utcccs-cdn.com/hvac/docs/1009/Public/04/OM-TPPACA-01.pdf
It says,

"SPECIAL FEATURES Hybrid Heat (heat pump with a furnace system
only)This thermostat works with the Carrier Hybrid Heat systems
offering maximum comfort and economy by automatically controlling
whether your system delivers heating with the heat pump, with the
furnace, or with both options working together."


Page 52
Hybrid Heat (heat pump with a furnace system only)page 47........This
Carrier heating and cooling system concept offers maximum
comfort and economy. When a Hybrid Heat system is installed,
the thermostat automatically controls whether your system delivers
heating with the heat pump, with the furnace,or with both options
working together.
Mikek

Doesn't say anything about electric back up vs. oil, etc...

One very good reason to not run the heat pump with the backup electric heat is the power required.

Why are you arguing that. I understand why you are trying to shut down
the auxiliary heat.

I'm saying the thermostat might not run both heats at the same time if the back up is electric because it would be a very large load at one time, 15 kW.


They have separate breakers, but the electric coils in my house are 10
kW or 40 amps requiring a 50 amp circuit. The outside unit would
require a 30 amp breaker. Just how much can you wire into a panel
before it becomes a problem? If the kitchen were drawing 5 kW or more,
the hot water heater was running at 10 kW (or more) and the dryer was
running at 8 kW, that's pretty durn close to the house hold max. Throw
in an iron fire up the microwave and a few light bulbs and the main
breaker might blow. One of my other houses, only having 100 amp
service, might have blown the main breaker before the dryer was turned
on, but for the fact it has oil backup.

Not helpful info.

So, do you think or can you find out, if the Thermostat has a separate
output when the thermostat has a high differential to fire up the oil
furnace?
Mikek

I took the thermostat off the mount and took some photos. Maybe I can dig up a manual. I have no other way of knowing what the thermostat will do, but I can assure you that there is not a special output for "high differential temperature". There is a signal to turn on the heat pump and a signal to run the electric coils. The furnace may or may not cut off the heat pump when the coils are on regardless of what the thermostat does.

I appreciate the help, but I'm not looking for someone to reverse engineer my heating system. Originally I was asking if anyone knew about a thermostat that would ramp up the temperature in a way that would not trigger the back up heat.

What is triggering the backup heat?

In the typical install, the thermostat makes the call, because it has the
best information, ie what the set temp is, what the actual is, how long
it's been running already. The Trane thermostat he has looks just like
the Honeywell Vision Pro series and that's how they work. He also says
that the thermostat has a wire for aux heat, that settles it for me.



Yes, it would seem to me that the thermostat would have a separate
wire going to the control board for Aux heat.
And that's what turns on the aux, weather it's electric or oil.





Does it just come on when the Heat pump comes on?
Probably no, I think you said it only comes on with either a
long run of the heat pump, or if the system has been off a long time.
One or the other, could you define that better for me?

It has gotten confusing. I thought he was saying that the aux heat
only comes on when it's needed, to supplement the heat pump.

Then the question is, How does the thermostat determine, "when it's needed".

I think they typically base it on how big the temp delta that it has to
close is. If it's one or two deg and the system has not been running
a lot just to maintain, then it uses heat pump only. If it's more
than about 2 deg or it's been running most of the time just to maintain
the temp, then it uses both.




It might help if he listed the setting install on the page,
https://www.manualslib.com/manual/461448/Trane-Tcont802as32da.html?page=12#manual
starting with Setup Number O170.

Like I said, that thermostat is surely made by Honeywell, it looks
just like the VisionPro Series. I have one, I looked at it's settings
and there is nothing there to control aux heat, with two exceptions

1 - You can enable or disable it

2 - If you have an optional external temp sensor, you can disable it
above 40 to 60F, where you get to set that temperature. The idea being
if it's say 50F outside, you know it works well enough that it can heat
without aux heat and you're willing to wait. I pointed that out before,
it would be a partial solution to disable aux heat some of the time,
if he sets it to 40F, at least it would not come on part of the time.
But maybe that is actually a solution for most of the time. When it's
below 40F out it may take so long to get the temp up with just the heat
pump that you'd want aux on anyway.
But hooking up an outside sensor could be a big issue and his thermostat
may not support it. You'd think some thermostats would have more prog
control over when it comes on, like at least how big the temp delta
has to be.

Until he tells me I have the wrong manual, I have to assume what I'm
seeing in the manual is correct.

 

[Whoey Louie]

On Tuesday, January 14, 2020 at 1:28:05 PM UTC-5, amdx wrote:

On 1/14/2020 12:11 PM, Whoey Louie wrote:
On Tuesday, January 14, 2020 at 12:41:14 PM UTC-5, amdx wrote:
On 1/14/2020 9:47 AM, Whoey Louie wrote:
On Tuesday, January 14, 2020 at 10:24:22 AM UTC-5, amdx wrote:
On 1/13/2020 4:28 PM, Rick C wrote:
On Monday, January 13, 2020 at 1:52:26 PM UTC-5, amdx wrote:
On 1/13/2020 12:08 PM, Rick C wrote:
On Monday, January 13, 2020 at 12:37:39 PM UTC-5, amdx wrote:
On 1/11/2020 11:03 AM, Rick C wrote:
On Saturday, January 11, 2020 at 8:49:50 AM UTC-5, Winfield Hill wrote:
Rick C wrote...

My heatpump runs anytime the temperature is above 40F
= 4.4C (this is adjustable). The thermostat calls for
"aux" heat (oil furnace) when the outside temperature
is below that. When aux heat runs, the heatpump is
entirely off. It's a 2014 Carrier "edge" thermostat.

Yes, you have posted about the limitations of your heatpump before. How is that relevant?

I suspect if you check with someone who knows, your backup heat will also run under two other conditions. One is the system detects ice on the outside coils. With a 40 degree cut off, your system might not worry with deicing. The other condition is when the system runs long enough that it decides the heat pump is not doing the job and switches to backup heat.. Opps, another condition is if the inside temperature drops too far bellow the set temperature.

The first heat pump I owned was very, very simple. It had a two bulb thermostat. Set the temperature and bulb 1 would control the heat to keep the temperature. But if the room (hallway as the case may be) temperature dropped too far the second bulb switch would close and the backup heat would come on.

That is the condition I am trying to avoid with a thermostat which ramps the temperature up slowly enough to not kick in the backup heat.

I don't know of any heat pump that isn't set to work that way. Ask your installer. With the last system I bought I found I could not even get info from the company who made it. They always referred me to the "installer", like I was not worthy of information.


My thinking is, the thermostat sees a high delta between the house
temperature and the set temperature. In order to correct that (for your
comfort) it turns on both heat pump and auxiliary heat.

I suspect there is a wire from the thermostat to the control board,
that develops an output when there is a high delta, this output tells

the control board to turn on Auxiliary heat.

The truth may lie elsewhere, but that's my analysis.


On page 47 of the Thermostat manual, if this is the manual,
http://www.utcccs-cdn.com/hvac/docs/1009/Public/04/OM-TPPACA-01..pdf
It says,

"SPECIAL FEATURES Hybrid Heat (heat pump with a furnace system
only)This thermostat works with the Carrier Hybrid Heat systems
offering maximum comfort and economy by automatically controlling
whether your system delivers heating with the heat pump, with the
furnace, or with both options working together."


Page 52
Hybrid Heat (heat pump with a furnace system only)page 47.........This
Carrier heating and cooling system concept offers maximum
comfort and economy. When a Hybrid Heat system is installed,
the thermostat automatically controls whether your system delivers
heating with the heat pump, with the furnace,or with both options
working together.
Mikek

Doesn't say anything about electric back up vs. oil, etc...

One very good reason to not run the heat pump with the backup electric heat is the power required.

Why are you arguing that. I understand why you are trying to shut down
the auxiliary heat.

I'm saying the thermostat might not run both heats at the same time if the back up is electric because it would be a very large load at one time, 15 kW.


They have separate breakers, but the electric coils in my house are 10
kW or 40 amps requiring a 50 amp circuit. The outside unit would
require a 30 amp breaker. Just how much can you wire into a panel
before it becomes a problem? If the kitchen were drawing 5 kW or more,
the hot water heater was running at 10 kW (or more) and the dryer was
running at 8 kW, that's pretty durn close to the house hold max. Throw
in an iron fire up the microwave and a few light bulbs and the main
breaker might blow. One of my other houses, only having 100 amp
service, might have blown the main breaker before the dryer was turned
on, but for the fact it has oil backup.

Not helpful info.

So, do you think or can you find out, if the Thermostat has a separate
output when the thermostat has a high differential to fire up the oil
furnace?
Mikek

I took the thermostat off the mount and took some photos. Maybe I can dig up a manual. I have no other way of knowing what the thermostat will do, but I can assure you that there is not a special output for "high differential temperature". There is a signal to turn on the heat pump and a signal to run the electric coils. The furnace may or may not cut off the heat pump when the coils are on regardless of what the thermostat does.

I appreciate the help, but I'm not looking for someone to reverse engineer my heating system. Originally I was asking if anyone knew about a thermostat that would ramp up the temperature in a way that would not trigger the back up heat.

What is triggering the backup heat?

In the typical install, the thermostat makes the call, because it has the
best information, ie what the set temp is, what the actual is, how long
it's been running already. The Trane thermostat he has looks just like
the Honeywell Vision Pro series and that's how they work. He also says
that the thermostat has a wire for aux heat, that settles it for me.



Yes, it would seem to me that the thermostat would have a separate
wire going to the control board for Aux heat.
And that's what turns on the aux, weather it's electric or oil.





Does it just come on when the Heat pump comes on?
Probably no, I think you said it only comes on with either a
long run of the heat pump, or if the system has been off a long time..
One or the other, could you define that better for me?

It has gotten confusing. I thought he was saying that the aux heat
only comes on when it's needed, to supplement the heat pump.

Then the question is, How does the thermostat determine, "when it's needed".

I think they typically base it on how big the temp delta that it has to
close is. If it's one or two deg and the system has not been running
a lot just to maintain, then it uses heat pump only. If it's more
than about 2 deg or it's been running most of the time just to maintain
the temp, then it uses both.




It might help if he listed the setting install on the page,
https://www.manualslib.com/manual/461448/Trane-Tcont802as32da.html?page=12#manual
starting with Setup Number O170.

Like I said, that thermostat is surely made by Honeywell, it looks
just like the VisionPro Series. I have one, I looked at it's settings
and there is nothing there to control aux heat, with two exceptions

1 - You can enable or disable it

2 - If you have an optional external temp sensor, you can disable it
above 40 to 60F, where you get to set that temperature. The idea being
if it's say 50F outside, you know it works well enough that it can heat
without aux heat and you're willing to wait. I pointed that out before,
it would be a partial solution to disable aux heat some of the time,
if he sets it to 40F, at least it would not come on part of the time.
But maybe that is actually a solution for most of the time. When it's
below 40F out it may take so long to get the temp up with just the heat
pump that you'd want aux on anyway.
But hooking up an outside sensor could be a big issue and his thermostat
may not support it. You'd think some thermostats would have more prog
control over when it comes on, like at least how big the temp delta
has to be.





Until he tells me I have the wrong manual, I have to assume what I'm
seeing in the manual is correct.

And what do you think you see in the manual? I see that it has the option
I told him about yesterday and that I just mentioned here again. Which
is if you have an external temp sensor, you can disable aux heat above
a temp between 40F and 60F, that you can set. That was from the Honeywell,
what you posted shows similar, though it might allow as low a setting as
35F. That would probably do what he wants some of the time,
probably most of the time.

 

[Rick C]

On Tuesday, January 14, 2020 at 10:24:22 AM UTC-5, amdx wrote:

On 1/13/2020 4:28 PM, Rick C wrote:
On Monday, January 13, 2020 at 1:52:26 PM UTC-5, amdx wrote:
On 1/13/2020 12:08 PM, Rick C wrote:
On Monday, January 13, 2020 at 12:37:39 PM UTC-5, amdx wrote:
On 1/11/2020 11:03 AM, Rick C wrote:
On Saturday, January 11, 2020 at 8:49:50 AM UTC-5, Winfield Hill wrote:
Rick C wrote...

My heatpump runs anytime the temperature is above 40F
= 4.4C (this is adjustable). The thermostat calls for
"aux" heat (oil furnace) when the outside temperature
is below that. When aux heat runs, the heatpump is
entirely off. It's a 2014 Carrier "edge" thermostat.

Yes, you have posted about the limitations of your heatpump before. How is that relevant?

I suspect if you check with someone who knows, your backup heat will also run under two other conditions. One is the system detects ice on the outside coils. With a 40 degree cut off, your system might not worry with deicing. The other condition is when the system runs long enough that it decides the heat pump is not doing the job and switches to backup heat. Opps, another condition is if the inside temperature drops too far bellow the set temperature.

The first heat pump I owned was very, very simple. It had a two bulb thermostat. Set the temperature and bulb 1 would control the heat to keep the temperature. But if the room (hallway as the case may be) temperature dropped too far the second bulb switch would close and the backup heat would come on.

That is the condition I am trying to avoid with a thermostat which ramps the temperature up slowly enough to not kick in the backup heat.

I don't know of any heat pump that isn't set to work that way. Ask your installer. With the last system I bought I found I could not even get info from the company who made it. They always referred me to the "installer", like I was not worthy of information.


My thinking is, the thermostat sees a high delta between the house
temperature and the set temperature. In order to correct that (for your
comfort) it turns on both heat pump and auxiliary heat.

I suspect there is a wire from the thermostat to the control board,
that develops an output when there is a high delta, this output tells

the control board to turn on Auxiliary heat.

The truth may lie elsewhere, but that's my analysis.


On page 47 of the Thermostat manual, if this is the manual,
http://www.utcccs-cdn.com/hvac/docs/1009/Public/04/OM-TPPACA-01.pdf
It says,

"SPECIAL FEATURES Hybrid Heat (heat pump with a furnace system
only)This thermostat works with the Carrier Hybrid Heat systems
offering maximum comfort and economy by automatically controlling
whether your system delivers heating with the heat pump, with the
furnace, or with both options working together."


Page 52
Hybrid Heat (heat pump with a furnace system only)page 47........This
Carrier heating and cooling system concept offers maximum
comfort and economy. When a Hybrid Heat system is installed,
the thermostat automatically controls whether your system delivers
heating with the heat pump, with the furnace,or with both options
working together.
Mikek

Doesn't say anything about electric back up vs. oil, etc...

One very good reason to not run the heat pump with the backup electric heat is the power required.

Why are you arguing that. I understand why you are trying to shut down
the auxiliary heat.

I'm saying the thermostat might not run both heats at the same time if the back up is electric because it would be a very large load at one time, 15 kW.


They have separate breakers, but the electric coils in my house are 10
kW or 40 amps requiring a 50 amp circuit. The outside unit would
require a 30 amp breaker. Just how much can you wire into a panel
before it becomes a problem? If the kitchen were drawing 5 kW or more,
the hot water heater was running at 10 kW (or more) and the dryer was
running at 8 kW, that's pretty durn close to the house hold max. Throw
in an iron fire up the microwave and a few light bulbs and the main
breaker might blow. One of my other houses, only having 100 amp
service, might have blown the main breaker before the dryer was turned
on, but for the fact it has oil backup.

Not helpful info.

So, do you think or can you find out, if the Thermostat has a separate
output when the thermostat has a high differential to fire up the oil
furnace?
Mikek

I took the thermostat off the mount and took some photos. Maybe I can dig up a manual. I have no other way of knowing what the thermostat will do, but I can assure you that there is not a special output for "high differential temperature". There is a signal to turn on the heat pump and a signal to run the electric coils. The furnace may or may not cut off the heat pump when the coils are on regardless of what the thermostat does.

I appreciate the help, but I'm not looking for someone to reverse engineer my heating system. Originally I was asking if anyone knew about a thermostat that would ramp up the temperature in a way that would not trigger the back up heat.

What is triggering the backup heat?

The only way to determine that is to instrument the whole thing and make measurements. I've not done that because it doesn't change the solution. The backup is coming on either because the temperature is too far from the set point, or because the heat has been running too long. The former can only be from the thermostat, the latter could be implemented in either.


> Does it just come on when the Heat pump comes on?

???

Probably no, I think you said it only comes on with either a
long run of the heat pump, or if the system has been off a long time.
One or the other, could you define that better for me?

Nope, I don't know. I've not opened the furnace and put a volt meter on the various components to see exactly when what runs. I don't plan to either.. Not useful info.


> What would cause you to want the oil furnace to come on?

When it is needed, but I don't have an oil furnace in this house. It has electric backup.

Can you you just put an on off switch in the oil furnace
turn on signal line?
That way, if you want oil heat just flip the switch.

Ok, you have completely missed the trolley and are headed to city center of off the mark ville.

If I have to roll my own thermostat I'm sure I can figure out what I
need to know to make it work.

The connector has the standard labeling of thermostats. The model is TCONT802AS32DAA Trane. I found manuals for it but they don't offer a lot of insight. I think a lot of this stuff is cut and dried and hasn't changed in 50 years or more. So they don't tell you any of the standard assumptions in the manuals.

Have you looked at this page?
https://www.manualslib.com/manual/461448/Trane-Tcont802as32da.html?page=18#manual


Does it apply to your thermostat setup?

Seems to.

I'm especially curious about #5.
#5. Choose appropriate Balance Point Temperature
in Installer Setup Number 0350.

Not sure what you are talking about "Balance Point Temperature". It says 0350 is for "Heat Pump Compressor Lockout". Doesn't sound useful to me.

There might be more info to glean from this thermostat setup page.
https://www.manualslib.com/manual/461448/Trane-Tcont802as32da.html?page=12#manual

I haven't found anything other than settings that have already been dealt with.

--

Rick C.

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