OT How does my car's AC work?

[Ron D.]

Defrost always runs the compressor though, so in the winter everybody uses it. At least in cars I've had.
=====

in a 1972 Chevelle, the AC and Defrost was linked although it may have been possible that at full hot, the AC got turned off. I can't remember, but i suspect not.

An 82 Celica allowed independent AC compressor on and off and a 2000 Chevy Impala did the same thing.

 

[Micky]

On Fri, 19 Aug 2016 22:43:32 -0700 (PDT), "Ron D."
<Ron.Dozier@gmail.com> wrote:

Defrost always runs the compressor though, so in the winter everybody uses it. At least in cars I've had.
=====

in a 1972 Chevelle, the AC and Defrost was linked although it may have been possible that at full hot, the AC got turned off. I can't remember, but i suspect not.

An 82 Celica allowed independent AC compressor on and off and a 2000 Chevy Impala did the same thing.

The 2000 Toyota turns the AC on when the defroster is turned on, but
it can be turned off by pressing the AC button.

The 84, 88, and 95 Lebarons had a separate switch for AC, a mechanical
switch where Off meant Off.

I don't think any of these cars had a MAX setting by that name.

 

Ron D. wrote: "in a 1972 Chevelle, the AC and Defrost was linked although it may have been possible that
at full hot, the AC got turned off. I can't remember, but i suspect not. "


I always made the simplistic assumption that the only
difference between "AC" and "Defrost" modes was the
direction the compressored air was ducted: either toward
your face and feet(AC), or out the top side of the dash
toward the windshield(Def).

A lot of owners manuals suggest a temperature setting
between "10 and 2 o'clock" when using Defrost, vs
extreme/full cold or hot, respectively, for AC or Heater.

 

On Wednesday, August 17, 2016 at 7:53:17 PM UTC-4, avag.ail.com wrote:

NO RECIRCULATE

recirculate is for a load of rotting fish.

___

Fresh air fanatics, are we?

 

On Monday, August 22, 2016 at 9:11:55 AM UTC-4, thekma...@gmail.com wrote:

On Wednesday, August 17, 2016 at 7:53:17 PM UTC-4, avag.ail.com wrote:
NO RECIRCULATE

recirculate is for a load of rotting fish.


___

Fresh air fanatics, are we?

I drive a van.....

defrost is both cool defrost and warm hot defrost .... in South Fla, Texas et al So Cal .....AC during a morning commute generates the Geese Pond Effect ...GPE .....requiring cool defrost.

recirculate gives coolest temps, mix is for rotting fish. sorry.

the 2008 Ford Econoline reads: MAX AC/NORM AC/VENT/OFF/FLR/MIX/then an ideogram for DEFROST. could be VENT is for rotting fish ? I could ask the dealer but then parts $$$ will go up.....

 

[Ron D.]

On Saturday, August 20, 2016 at 7:21:00 AM UTC-4, Micky wrote:

On Fri, 19 Aug 2016 22:43:32 -0700 (PDT), "Ron D."
wrote:

Defrost always runs the compressor though, so in the winter everybody uses it. At least in cars I've had.
====
in a 1972 Chevelle, the AC and Defrost was linked although it may have been possible that at full hot, the AC got turned off. I can't remember, but i suspect not.

An 82 Celica allowed independent AC compressor on and off and a 2000 Chevy Impala did the same thing.

The 2000 Toyota turns the AC on when the defroster is turned on, but
it can be turned off by pressing the AC button.

Some versions of Windows, you go to the "Start" menu. Some things rub off. <G>.

The 84, 88, and 95 Lebarons had a separate switch for AC, a mechanical
switch where Off meant Off.

I don't think any of these cars had a MAX setting by that name.

The Celica didn't have a setting labeled MAX, but the control module needed to know. My guess would be that if the evaporator got too cold and it was in recirculate, open 1/2 of the re-circulate door. If it was not in recirculate, then turn off the compressor if the evaporator got too cold. The temp lever mechanically controlled a water valve.

I tried to look up the parts, but seeing how the door worked wasn't really possible. The real reason I knew is because I installed all of the pieces.

When a 1968 Chrysler "Aftermarket" AC got too cold, you would get water on your feet on turns. They made units that would bolt under the dash in that ERA. This particular mounting bracket used the thermostat housing to mount the compressor.

 

[Ron D.]

On Sunday, August 21, 2016 at 8:09:09 PM UTC-4, thekma...@gmail.com wrote:

Ron D. wrote: "in a 1972 Chevelle, the AC and Defrost was linked although it may have been possible that
at full hot, the AC got turned off. I can't remember, but i suspect not. "


I always made the simplistic assumption that the only
difference between "AC" and "Defrost" modes was the
direction the compressored air was ducted: either toward
your face and feet(AC), or out the top side of the dash
toward the windshield(Def).

A lot of owners manuals suggest a temperature setting
between "10 and 2 o'clock" when using Defrost, vs
extreme/full cold or hot, respectively, for AC or Heater.

DEFROST - when there is ice or snow on the windshield

DEFOG - When there is water on the inside of the window. The Dew point determines when this occurs. Lowering the humidity of the air increases the heat capacity of the conditioned air and raises the dew point.

It's hard to get people to use the AC and Heat at the same time especially when it's cold out and you want to get warm. From a Thermodynamic view, it doesn't work.

See, I use thermodynamics in everyday life. Hot water freezes faster than cold water does. Ice expands when cooled. Increasing surface area increases heat loss. A hat will increase body temperature significantly, A hat prevents heat loss from your head. layering clothes is important. I somewhat regulate sleeping temperature by wearing one, two or no socks to bed. A bare foot in a slipper with an air gap will be warmer than a slipper, and a tight fitting sock. Wet clothes are bad when trying to stay warm.

 

Ron D. wrote: " DEFROST - when there is ice or snow on the windshield

DEFOG - When there is water on the inside of the window. The Dew point determines when this occurs. Lowering the humidity of the air increases
the heat capacity of the conditioned air and raises the dew point. "

Thanks for that detailed explanation. Most car climate controls
abbreviate it to "DEF", and I always assumed it was short for
defrost.



"It's hard to get people to use the AC and Heat at the same time especially when it's cold out and you want to get warm. From a Thermodynamic view,
it doesn't work."

Again, what I wrote were the suggested temperature knob settings
for defrost/defog/de-what-ever. For Heat and AC, the temperature
knob positions should be obvious - although my particular owners
manual suggests setting temperature knob to approximately the 10
o'clock position when using the Auto climate feature for cooling in
summer, and 2 o'clock for heating in winter. I followed the instructions
for Auto in summer and so far, has been transparent and satisfactory.



"See, I use thermodynamics in everyday life. Hot water freezes faster than cold water does. Ice expands when cooled. Increasing surface area increases
heat loss. A hat will increase body temperature significantly, A hat prevents heat loss from your head. layering clothes is important. I somewhat regulate
sleeping temperature by wearing one, two or no socks to bed. A bare foot in a slipper with an air gap will be warmer than a slipper, and a tight fitting sock.
Wet clothes are bad when trying to stay warm. "

Nice tips. So it's the air between skin and clothing, and between
layers, that keeps one warm.

 

>"Ice expands when cooled."

No, ice only expands when it becomes ice.

 

[Micky]

On Wed, 24 Aug 2016 02:13:46 -0700 (PDT), "Ron D."
<Ron.Dozier@gmail.com> wrote:

When a 1968 Chrysler "Aftermarket" AC got too cold, you would get water on your feet on turns. They made units that would bolt under the dash in that ERA. This particular mounting bracket used the thermostat housing to mount the compressor.

My mother had a '65 Plymouth Fury II with an aftermarket AC. I think
it worked pretty well. Not all the vents of factory AC, I think, but
it wasn't so hot back then.

 

[Ron D.]

On Monday, August 29, 2016 at 12:13:42 AM UTC-4, Micky wrote:

On Wed, 24 Aug 2016 02:13:46 -0700 (PDT), "Ron D."
wrote:



When a 1968 Chrysler "Aftermarket" AC got too cold, you would get water on your feet on turns. They made units that would bolt under the dash in that ERA. This particular mounting bracket used the thermostat housing to mount the compressor.

My mother had a '65 Plymouth Fury II with an aftermarket AC. I think
it worked pretty well. Not all the vents of factory AC, I think, but
it wasn't so hot back then.

That too.

Sorry about the ice expansion thing: Yep the volume of ice is larger than the volume of water used to create the ice.

 

On Tuesday, August 30, 2016 at 1:23:27 AM UTC-4, Ron D. wrote:

On Monday, August 29, 2016 at 12:13:42 AM UTC-4, Micky wrote:
On Wed, 24 Aug 2016 02:13:46 -0700 (PDT), "Ron D."
wrote:



When a 1968 Chrysler "Aftermarket" AC got too cold, you would get water on your feet on turns. They made units that would bolt under the dash in that ERA. This particular mounting bracket used the thermostat housing to mount the compressor.

My mother had a '65 Plymouth Fury II with an aftermarket AC. I think
it worked pretty well. Not all the vents of factory AC, I think, but
it wasn't so hot back then.

That too.

Sorry about the ice expansion thing: Yep the volume of ice is larger than the volume of water used to create the ice.

water volume changes, weak bonding are foundations of life on earth ....