Odd timer needed

[Jane Galt]

We're in the dry Denver area with a 2300 sq ft ranch home and have an
Aprilaire whole house humidifier with a wall thermostat. It uses a small line
of regulated 140 degree water from the water heater. The problem is, by the
time it comes on, it can stay on for hours. This causes what they call
"stacking" in the water heater, as it draws a tiny stream of hot water from
the top, causing cold water to come in the bottom and trigger the gas burner,
but then the top water overheats and gets WAY too hot, if it keeps running
for hours. We sometimes get hot water coming out of the overflow valve on the
water heater because of this.

And yes, we've thought of turning the water heater down - the problem is that
when the humidifier isn't running, then the hot water is the minimum temp we
need it, so it would be too cool to sustain a shower if we set it any lower.

So what I'm thinking, is we could put a timer in series with the humidistat,
which uses 120VAC in the series loop.

But the timer would have to allow it to run for an hour ( adjustable time )
when it comes on, then shut it off for a longer adjustable time so it doesn't
heat up the water way too much ( maybe 3 hours ) then let it run again. It
would have to be a series thing - sense that 120vac current was going through
it, let it go for an adjustable time, then shut off for an adjustable time,
then let it go again.

Is there even anything like that available, in an in-the wall series timer?

 

Jane Galt <Jane@whoisjanegalt.net> wrote:

comes on, it can stay on
for hours. This causes what they call "stacking" in the water heater,
as it draws a tiny stream of hot water from the top, causing cold
water to come in the bottom and trigger the gas burner, but then the
top water overheats and gets WAY too hot, if it keeps running for
hours.

Are you sure the humidifier is operating correctly and is sized
correctly for the house? Assuming the humidistat is operating
correctly, if it wants to run the humdifier for long periods of time,
maybe the humidifier isn't working as efficiently as it should be. Or,
maybe the humidistat isn't working right, and replacing it would help.

And yes, we've thought of turning the water heater down - the problem
is that when the humidifier isn't running, then the hot water is the
minimum temp we need it, so it would be too cool to sustain a shower
if we set it any lower.

You can get a small electric circulator pump that connects to the hot
water line and pumps water back to the water heater. This would
probably even out the temperature in your water heater, and also give
you hot water quicker at the faucet.

Or, you can get small water heaters that are designed to run a single
hot water faucet, either tank-type (a few gallons) or instant. Maybe
installing one of these to serve just the humidifer would help.

So what I'm thinking, is we could put a timer in series with the
humidistat, which uses 120VAC in the series loop.

You could use a plain old light timer - the kind that lets you set an
on or off for every hour of the day - in the 120 V supply to the
humidifier. Set it for 1 hour on, 3 hours off, around the clock.
This is easy to do (it doesn't need current sensing), but has the
disadvantage that when the humidistat calls for humidity, the timer
might be in its "off" cycle for a few more hours.

On the other hand, adding the timer is probably going to make the timer
the dominant variable in the equation. If the humidistat calls for
humidity for several hours, the timer will prevent the humidifer from
ever satisfying the request, unless the humidity in the house goes up
for some other reason. So the humidifer will just cycle on and off
with the timer.

It would have to be a series thing - sense that 120vac current was
going through it, let it go for an adjustable time, then shut off for
an adjustable time, then let it go again.

The timer also has to default to the "on" (contacts closed) state, so
it can tell if the humidifier is drawing any current or not. It doesn't
start the clock until it sees the humidifier drawing current, but the
contacts have to be closed so the humidifier *can* draw current.

I don't know if you can get a timer that does this all on its own. I
know you can get current sensing relays that close a set of contacts
when they detect current in another wire; Aprilaire even makes one for
enabling the humidifier with the furnace blower on furnaces that don't
have separate humidifier terminals, and "general purpose" ones are
available from Functional Devices
http://www.functionaldevices.com/building-automation/currentsensors.php
and probably others. Once you have the current-sensing relay, you'd
have to add a timer to it, maybe using a time-day relay. Amperite
http://www.amperite.com/search/search.aspx and other vendors make
these.

Again - if this is a widespread problem, I think Aprilaire would
probably sell it as an add-on box, or as a feature on a high-end
humidifer. So maybe adding a timer isn't the way this typically gets
solved.

Standard disclaimers apply; I don't get money or other consideration
from any companies mentioned.

Matt Roberds

 

[Ian Malcolm]

Jane Galt <Jane@WhoIsJaneGalt.net> wrote in
news:XnsA1207A449750EJaneWhoIsJaneGaltnet@216.196.121.131:

We're in the dry Denver area with a 2300 sq ft ranch home and have an
Aprilaire whole house humidifier with a wall thermostat. It uses a
small line of regulated 140 degree water from the water heater. The
problem is, by the time it comes on, it can stay on for hours. This
causes what they call "stacking" in the water heater, as it draws a
tiny stream of hot water from the top, causing cold water to come in
the bottom and trigger the gas burner, but then the top water
overheats and gets WAY too hot, if it keeps running for hours. We
sometimes get hot water coming out of the overflow valve on the water
heater because of this.

And yes, we've thought of turning the water heater down - the problem
is that when the humidifier isn't running, then the hot water is the
minimum temp we need it, so it would be too cool to sustain a shower
if we set it any lower.

So what I'm thinking, is we could put a timer in series with the
humidistat, which uses 120VAC in the series loop.

Reasons not to have been covered by Matt Roberds

I have an alternative suggestion for you. The water heater presumably can
be (or is) controlled by an external programmer so has a terminal for an
electrical control signal, (If not, you need someone experienced to hack
its thermostat circuit) so all you need is an auxillary thermostat right at
the top of its tank that detects the over-temperature condition and cuts
the control signal until it has dropped back to near normal working
temperature.

Result: It 'stacks' till its lets say 15 degrees too hot, then stays off
till its droppped back to within 5 degrees of your usual setting, and
repeats indefinately.

However I suspect that local electrical heating for the humidifier feed
would be cheaper to run long-term even if it is significantly more costly
to set up.

--
Ian Malcolm. London, ENGLAND. (NEWSGROUP REPLY PREFERRED)
ianm[at]the[dash]malcolms[dot]freeserve[dot]co[dot]uk
[at]=@, [dash]=- & [dot]=. *Warning* HTML & >32K emails --> NUL

 

[Jon Elson]

Jane Galt wrote:

We're in the dry Denver area with a 2300 sq ft ranch home and have an
Aprilaire whole house humidifier with a wall thermostat. It uses a small
line of regulated 140 degree water from the water heater. The problem is,
by the time it comes on, it can stay on for hours. This causes what they
call "stacking" in the water heater, as it draws a tiny stream of hot
water from the top, causing cold water to come in the bottom and trigger
the gas burner, but then the top water overheats and gets WAY too hot, if
it keeps running for hours. We sometimes get hot water coming out of the
overflow valve on the water heater because of this.
Is it really necessary to run hot water to the humidifier?

I had a house with forced-air heat, and worked up in stages to a HUGE
in-duct humidifier. It ran from the cold water tap, and worked fine.
Is yours in the heating ducts or a separate unit that sits on the floor,
with a fan, maybe? If in the ducts, the heat from the hot water heater
seems totally unnecessary, the hot air will do the job.

Our current house has hydronic heat, which is really NICE, quiet, clean,
etc. but doesn't allow you to attach a humidifier, as there are no
ducts. I built a frankenstein monster with a pot heated by a heating
element, and refilled by a float sensor and a solenoid valve. It works
great, but the humidity is not blown around as well without the forced air.

Jon

 

Ian Malcolm <See.My.Sig.for.email@totally.invalid> wrote:

Jane Galt <Jane@WhoIsJaneGalt.net> wrote in
news:XnsA1207A449750EJaneWhoIsJaneGaltnet@216.196.121.131:

This causes what they call "stacking" in the water heater, as it
draws a tiny stream of hot water from the top, causing cold water to
come in the bottom and trigger the gas burner, but then the top water
overheats and gets WAY too hot, if it keeps running for hours.

I have an alternative suggestion for you. The water heater presumably
can be (or is) controlled by an external programmer so has a terminal
for an electrical control signal, (If not, you need someone
experienced to hack its thermostat circuit)

Probably the most common type of water heater in single-family homes in
the US is entirely self-contained, with no external programmer. There
is a tank of somewhere between 30 to 60 gallons (110 to 220 liters), and
either a gas burner or some electric heating elements. The heater tries
to keep the entire volume of the tank at the set temperature.

The gas burner has a standing pilot; a thermocouple in the pilot flame
shuts off the gas valve if the pilot goes out. (The gas valve usually
has no other source of electricity.) The gas valve also has a
thermostat in it, which opens the gas supply to the main burner when the
water in the tank gets too cold, and shuts the gas off again when the
water is hot enough. The thermostat is usually set by a knob on the
side of the gas valve. This kind of water heater will still work even
during a power failure.

Electric water heaters have a line (mains) voltage thermostat on the
side of the tank that controls the heating elements. It is usually set
by removing a cover from the side of the tank and turning a small knob
with a screwdriver. Obviously, during a power failure, you are out of
luck with one of these.

A variation on the gas heater is a "pilotless" heater, which does need
line voltage (mains) to operate; when the thermostat calls for heat, a
spark igniter comes on to light the main burner. Some of these also
have an electric draft fan to make sure the exhaust gets outside. These
save gas and emissions, but don't work during a power failure.

There are other things ("tankless" heaters that do tend to have either
local or remote control panels that can be tapped into, combined water
and space heating boilers, solar heating, etc), but from the original
description, Jane has a tank-type gas water heater.

Matt Roberds

 

[Jane Galt]

mroberds@att.net wrote :

Jane Galt <Jane@whoisjanegalt.net> wrote:
The problem is, by the time [the humidifier] comes on, it can stay on
for hours. This causes what they call "stacking" in the water heater,
as it draws a tiny stream of hot water from the top, causing cold
water to come in the bottom and trigger the gas burner, but then the
top water overheats and gets WAY too hot, if it keeps running for
hours.

Are you sure the humidifier is operating correctly and is sized
correctly for the house?

Yes.

Assuming the humidistat is operating
correctly, if it wants to run the humdifier for long periods of time,
maybe the humidifier isn't working as efficiently as it should be. Or,
maybe the humidistat isn't working right, and replacing it would help.

No on both those things. We have the Aprilaire 360:

http://www.aprilaire.com/index.php?znfAction=ProductDetails&category=5
&item=350

It uses hot water at 140 degrees and blows it out over a pad. Humidifiers
work over periods of time. This one puts out about 1/2 gallon per hour.
Putting it out too fast might tend to cause condensing moisture.

And yes, we've thought of turning the water heater down - the problem
is that when the humidifier isn't running, then the hot water is the
minimum temp we need it, so it would be too cool to sustain a shower
if we set it any lower.

You can get a small electric circulator pump that connects to the hot
water line and pumps water back to the water heater.

Yes, a circulating loop around the house. But that requires adding plumbing
and the pump, and this is a UBC modular house that was put on a regular
foundation, but it still has plastic and insulation beneath it, so that
would cost a LOT in labor.

This would
probably even out the temperature in your water heater, and also give
you hot water quicker at the faucet.

Would love to, except for above.

Or, you can get small water heaters that are designed to run a single
hot water faucet, either tank-type (a few gallons) or instant. Maybe
installing one of these to serve just the humidifer would help.

More expense we cant afford...

So what I'm thinking, is we could put a timer in series with the
humidistat, which uses 120VAC in the series loop.

You could use a plain old light timer - the kind that lets you set an
on or off for every hour of the day - in the 120 V supply to the
humidifier. Set it for 1 hour on, 3 hours off, around the clock.
This is easy to do (it doesn't need current sensing), but has the
disadvantage that when the humidistat calls for humidity, the timer
might be in its "off" cycle for a few more hours.

Yeah but that sounds good actually. Let it run for half an hour and then 2
hours later for half an hour.

What it's doing now is running once or twice a day for 2-3 hours.

On the other hand, adding the timer is probably going to make the timer
the dominant variable in the equation. If the humidistat calls for
humidity for several hours, the timer will prevent the humidifer from
ever satisfying the request, unless the humidity in the house goes up
for some other reason. So the humidifer will just cycle on and off
with the timer.

Yeah. In fact I can even use a plug in one, right at where the humidifier
plugs into the AC in the laundry room. I suppose it will have to be an
appliance timer, because of the motor, but no problems with that! And I'll
get a mechanical one, so it doesn't need backup batteries or anything. It
won't matter if the power goes off or daylight savings or any of that,
because it simply limits the thing to half an hour of run time several
times a day.

Thanks Matt! Great suggestion!

 

Jane Galt <Jane@whoisjanegalt.net> wrote:

mroberds@att.net wrote :

You can get a small electric circulator pump that connects to the hot
water line and pumps water back to the water heater.

Yes, a circulating loop around the house. But that requires adding
plumbing and the pump,

I thought it would too, until I looked at the directions (online) for
the Watts pump that Home Depot sells. For that one, the pump goes at
the water heater. The "return" is provided by a valve that connects
between the hot and cold water lines at a sink; apparently it lets water
flow from the "hot" side to the "cold" side whenever somebody turns on a
cold water tap. The idea is to avoid having to run a pipe back from the
furthest faucet to the water heater. I have no idea how well this works
in practice; I just know it exists.

Yeah but that sounds good actually. Let it run for half an hour and
then 2 hours later for half an hour.

What it's doing now is running once or twice a day for 2-3 hours.

Just make sure you let it run "enough". 0.5 hours out of every 2 would
be 6 hours total, which matches what it is doing now. Otherwise, you
will end up with lower average humidity in the house.

You might also check that the humidifer returns to the previous setting
by itself after incoming power is lost. Just unplug it while it is
running, wait several minutes, plug it back in, and see if it starts up
again. (Mechanical appliance controls have no problem with this; some
electronic ones always default to "off" after a power failure.)

Matt Roberds

 

[Jasen Betts]

On 2012-12-07, Jane Galt <Jane@WhoIsJaneGalt.net> wrote:

mroberds@att.net wrote :

It uses hot water at 140 degrees and blows it out over a pad. Humidifiers
work over periods of time. This one puts out about 1/2 gallon per hour.
Putting it out too fast might tend to cause condensing moisture.

Yes, a circulating loop around the house. But that requires adding plumbing
and the pump, and this is a UBC modular house that was put on a regular
foundation, but it still has plastic and insulation beneath it, so that
would cost a LOT in labor.

you just need enough flow to stir the water in the tank, you don't need to
circulate the water around the house

perhaps a thermostat set at a higher temperature than the heater
thermostat mounted near the top of the tank that turns on a pump to
stir the water when it detects the overhot water.

Set it for 1 hour on, 3 hours off, around the clock.
This is easy to do (it doesn't need current sensing), but has the
disadvantage that when the humidistat calls for humidity, the timer
might be in its "off" cycle for a few more hours.

Yeah but that sounds good actually. Let it run for half an hour and then 2
hours later for half an hour.


Yeah. In fact I can even use a plug in one, right at where the humidifier
plugs into the AC in the laundry room. I suppose it will have to be an
appliance timer, because of the motor, but no problems with that! And I'll
get a mechanical one, so it doesn't need backup batteries or anything. It
won't matter if the power goes off or daylight savings or any of that,
because it simply limits the thing to half an hour of run time several
times a day.

should work, but if the humidifier hs a cycle it should complete
before it shuts down, fitting the timer will disrupt that. it it meant
to dry the pad out before it shuts down?

--
⚂⚃ 100% natural

--- news://freenews.netfront.net/ - complaints: news@netfront.net ---

 

[Jane Galt]

mroberds@att.net wrote :

Jane Galt <Jane@whoisjanegalt.net> wrote:
mroberds@att.net wrote :

You can get a small electric circulator pump that connects to the hot
water line and pumps water back to the water heater.

Yes, a circulating loop around the house. But that requires adding
plumbing and the pump,

I thought it would too, until I looked at the directions (online) for
the Watts pump that Home Depot sells. For that one, the pump goes at
the water heater. The "return" is provided by a valve that connects
between the hot and cold water lines at a sink; apparently it lets water
flow from the "hot" side to the "cold" side whenever somebody turns on a
cold water tap. The idea is to avoid having to run a pipe back from the
furthest faucet to the water heater. I have no idea how well this works
in practice; I just know it exists.

It appears that you can put the loop on a timer for the times you shower,
but it could also send scalding water up through the cold line. How would
you regulate it?

Yeah but that sounds good actually. Let it run for half an hour and
then 2 hours later for half an hour.

What it's doing now is running once or twice a day for 2-3 hours.

Just make sure you let it run "enough". 0.5 hours out of every 2 would
be 6 hours total, which matches what it is doing now. Otherwise, you
will end up with lower average humidity in the house.

It's installed for over a week now, and seems to be working very well,
thanks!

You might also check that the humidifer returns to the previous setting
by itself after incoming power is lost. Just unplug it while it is
running, wait several minutes, plug it back in, and see if it starts up
again. (Mechanical appliance controls have no problem with this; some
electronic ones always default to "off" after a power failure.)

I actually bought one of the mechanical timers and set it to run for a half
hour out of every 2.5 hours. So if the power goes off, it doesn't matter,
it just starts up again and runs. There's no absolute time setting needed
this way, it doesn't matter where the dial is.

 

[Jane Galt]

Jasen Betts <jasen@xnet.co.nz> wrote :

On 2012-12-07, Jane Galt <Jane@WhoIsJaneGalt.net> wrote:
mroberds@att.net wrote :


It uses hot water at 140 degrees and blows it out over a pad.
Humidifiers work over periods of time. This one puts out about 1/2
gallon per hour. Putting it out too fast might tend to cause condensing
moisture.

Yes, a circulating loop around the house. But that requires adding
plumbing and the pump, and this is a UBC modular house that was put on
a regular foundation, but it still has plastic and insulation beneath
it, so that would cost a LOT in labor.

you just need enough flow to stir the water in the tank, you don't need
to circulate the water around the house

perhaps a thermostat set at a higher temperature than the heater
thermostat mounted near the top of the tank that turns on a pump to
stir the water when it detects the overhot water.

Hadn't thought about that, and thanks! Seems simple enough to just put a
tiny pump in to circulate the water from the top of the tank to the bottom,
constantly.

Set it for 1 hour on, 3 hours off, around the clock.
This is easy to do (it doesn't need current sensing), but has the
disadvantage that when the humidistat calls for humidity, the timer
might be in its "off" cycle for a few more hours.

Yeah but that sounds good actually. Let it run for half an hour and
then 2 hours later for half an hour.


Yeah. In fact I can even use a plug in one, right at where the
humidifier plugs into the AC in the laundry room. I suppose it will
have to be an appliance timer, because of the motor, but no problems
with that! And I'll get a mechanical one, so it doesn't need backup
batteries or anything. It won't matter if the power goes off or
daylight savings or any of that, because it simply limits the thing to
half an hour of run time several times a day.

should work, but if the humidifier hs a cycle it should complete
before it shuts down, fitting the timer will disrupt that. it it meant
to dry the pad out before it shuts down?

 

Jane Galt <Jane@whoisjanegalt.net> wrote:

mroberds@att.net wrote :

For that one, the pump goes at the water heater. The "return" is
provided by a valve that connects between the hot and cold water lines
at a sink; apparently it lets water flow from the "hot" side to the
"cold" side whenever somebody turns on a cold water tap.

It appears that you can put the loop on a timer for the times you
shower, but it could also send scalding water up through the cold line.
How would you regulate it?

I don't know exactly how it works. It could be that the remote valve
meters a small enough amount of hot water into the cold side that it
doesn't raise the temperature of the cold side that much. The remote
valve is supposed to go at the sink that is farthest from the water
heater, so some of the "hot" water that it flows into the cold line
won't be that hot by the time it gets there.

(Mechanical appliance controls have no problem with this; some
electronic ones always default to "off" after a power failure.)

I actually bought one of the mechanical timers and set it to run for a
half hour out of every 2.5 hours. So if the power goes off, it doesn't
matter, it just starts up again and runs.

Right. I was thinking of the timer or control that is already built
into the appliance itself (in this case, the humidifier). For instance,
if you have an older dishwasher with an electromechanical timer, and the
power goes out while it's halfway through the cycle, nothing really bad
happens - the timer motor just stops where it is. When the power comes
back, everything picks up where it left off - the wash or rinse might
not be as effective if the water has cooled off, but it should go on and
complete the cycle. A newer dishwasher, with electronic controls, will
also stop when the power goes out, but when the power comes back, it may
stay in "stop" mode, waiting for somebody to push the button again.

As long as your humidifier just starts back up again when the timer you
added switches on, then everything is OK.

Matt Roberds

 

[Jane Galt]

mroberds@att.net wrote :

Jane Galt <Jane@whoisjanegalt.net> wrote:
mroberds@att.net wrote :

For that one, the pump goes at the water heater. The "return" is
provided by a valve that connects between the hot and cold water lines
at a sink; apparently it lets water flow from the "hot" side to the
"cold" side whenever somebody turns on a cold water tap.

It appears that you can put the loop on a timer for the times you
shower, but it could also send scalding water up through the cold line.
How would you regulate it?

I don't know exactly how it works. It could be that the remote valve
meters a small enough amount of hot water into the cold side that it
doesn't raise the temperature of the cold side that much. The remote
valve is supposed to go at the sink that is farthest from the water
heater, so some of the "hot" water that it flows into the cold line
won't be that hot by the time it gets there.

(Mechanical appliance controls have no problem with this; some
electronic ones always default to "off" after a power failure.)

I actually bought one of the mechanical timers and set it to run for a
half hour out of every 2.5 hours. So if the power goes off, it doesn't
matter, it just starts up again and runs.

Right. I was thinking of the timer or control that is already built
into the appliance itself (in this case, the humidifier). For instance,
if you have an older dishwasher with an electromechanical timer, and the
power goes out while it's halfway through the cycle, nothing really bad
happens - the timer motor just stops where it is. When the power comes
back, everything picks up where it left off - the wash or rinse might
not be as effective if the water has cooled off, but it should go on and
complete the cycle. A newer dishwasher, with electronic controls, will
also stop when the power goes out, but when the power comes back, it may
stay in "stop" mode, waiting for somebody to push the button again.

As long as your humidifier just starts back up again when the timer you
added switches on, then everything is OK.

Matt Roberds

Yeah, it's great.

 

[josephkk]

On Sun, 16 Dec 2012 14:05:34 -0600, Jane Galt <Jane@WhoIsJaneGalt.net>
wrote:

mroberds@att.net wrote :

Jane Galt <Jane@whoisjanegalt.net> wrote:
mroberds@att.net wrote :

You can get a small electric circulator pump that connects to the hot
water line and pumps water back to the water heater.

Yes, a circulating loop around the house. But that requires adding
plumbing and the pump,

I thought it would too, until I looked at the directions (online) for
the Watts pump that Home Depot sells. For that one, the pump goes at
the water heater. The "return" is provided by a valve that connects
between the hot and cold water lines at a sink; apparently it lets water
flow from the "hot" side to the "cold" side whenever somebody turns on a
cold water tap. The idea is to avoid having to run a pipe back from the
furthest faucet to the water heater. I have no idea how well this works
in practice; I just know it exists.


It appears that you can put the loop on a timer for the times you shower,
but it could also send scalding water up through the cold line. How would
you regulate it?


Yeah but that sounds good actually. Let it run for half an hour and
then 2 hours later for half an hour.

What it's doing now is running once or twice a day for 2-3 hours.

Just make sure you let it run "enough". 0.5 hours out of every 2 would
be 6 hours total, which matches what it is doing now. Otherwise, you
will end up with lower average humidity in the house.

It's installed for over a week now, and seems to be working very well,
thanks!

You might also check that the humidifer returns to the previous setting
by itself after incoming power is lost. Just unplug it while it is
running, wait several minutes, plug it back in, and see if it starts up
again. (Mechanical appliance controls have no problem with this; some
electronic ones always default to "off" after a power failure.)

I actually bought one of the mechanical timers and set it to run for a half
hour out of every 2.5 hours. So if the power goes off, it doesn't matter,
it just starts up again and runs. There's no absolute time setting needed
this way, it doesn't matter where the dial is.


Nice to hear your selected solution works for you. OTOH i expect 1/2 or

1/3 duty cycle will work as well as the present 1/6 duty cycle. You may
need to buy some tabs or things though.

?-)