Honda Car Forum

Philip,
We're talking about two different controls. There are sensors, or in older
cars, capillary tubes at the evaporators monitoring evap temp to control
what you're talking about, evaporator icing. In late model cars that also
cycled the compressor as that was how pressure/flow of refrigerant was
maintained. But there is also an ambient temp sensor that would not allow
the compressor to run below a certain outside air temp in order to prevent
hydraulic lock-up of the compressor due to refrigerant being in a liquid
state in the comp head. Refrigerant "boils" and becomes vapor at a low
temp, that's one of the reason it's used as a refrigerant. If the temp
drops below that "boiling point" on the low pressure side the gas will
condense back into a liquid and hydraulicly lock up the compressor. I
mentioned the diference in the refrigerants as a possible explanation for
why the posters old lincoln a/c would run at temps below his late model
mustang, however I was simply stating that the American government didn't
regulate this 40F cutout, the laws of physics did.
Steve.
"Philip" <1chip-state1@earthlink.net> wrote in message
news:4nQxd.6785$yK.4838@newsread3.news.atl.earthli nk.net...
> Has nothing to do with the refrigerant. Has solely to do with the
> temperature water freezes at ... 32 degrees. Since in most cases, all air
> flows thru the evaporator and then to or past the heater core, were the
> water on the evaporator be allowed to freeze solid, no air would flow out
of
> any of the plenum chamber outlets.
> --
>
> - Philip
>
> "Steve G" <NospamforSteve@Steve-Garner.com> wrote in message
> news:0ZOxd.534980$Pl.108826@pd7tw1no
> > The low temp cutout may have different settings, but that is most
> > likely a result of the diferent refrigerants used, r12 vs 134a,
> > Your 83 may still run at 40, but there is a temp close to that
> > where it will no longer engage. They all had low temp cutouts for
> > the very reason I mentioned. Or, the low temp cutout may have been
> > by-passed or is not working properly. Take it out on a cold frosty
> > morning and run the ac and let us know what happens.
> > I'm a mechanic by trade (inter-provincially licensed) and worked in
> > the field in the 70's and 80's and never saw a compressor cycle in
> > temp below 35 to 40 F. Up here in the frozen north of Canada we
> > use our defrost a lot and they would engage the compressor in the
> > mild weather, but have never seen a compressor run in the cold.
> > Not sure what it has to do with buying a 3 gal toilet tho...
> > <MajorDomo@mailcity.com> wrote in message
> > news:41C78DD7.991EF9E3@mailcity.com...
> >> You certainly are entitle to your own opinion. The AC on my 83
> >> Continental will run below 40 degrees but not my 2005 Lincoln LS
> >> or my 2003 Mustang GT. Go try a buy a three gallon toilet or a
> >> new model top loading washing machine in the US today.
> >>
> >>
> >> mike hunt
> >>
> >>
> >>
> >> Steve G wrote:
> >>>
> >>> No it's not!
> >>> AC systems have always had low temp cutouts on them, and it's not
> >>> idiocy for the above poster. The ac is called for anytime the
> >>> defrost is selected on most cars but is prevented from cutting in
> >>> below 40 F because below that temp the gaseous refrigerant will
> >>> liquefy and as we all know you can not compress a liquid. It
> >>> cuts it out so that your compressor doesn't smash to little bits
> >>> trying to compress liquid refrigerant.
> >>> Short lesson in refrigeration, compressor draws in low pressure
> >>> gas, pumps out high pressure gas. High pressure gas condenses
> >>> into a liquid under pressure in... what else but the condenser
> >>> (that other rad in the front of your car). High pressure liquid
> >>> is metered/sprayed into the evaporator where it becomes a low
> >>> pressure gas again and so on.
> >>>
> >>> For the OP, cars with persistant high humidity situations
> >>> sometimes have water leaks that may not be apparent. I had a
> >>> Supra that leaked water
> > at
> >>> the hatch. Windows seemed to fog easily. Discovered one day
> >>> that the spare tire well was half full of water.
> >>> Steve
> >>> <MajorDomo@mailcity.com> wrote in message
> >>> news:41C78298.78A50057@mailcity.com...
> >>>> The deactivation on newer domestic and automotive AC's, at 40
> >>>> degrees, is a federal regulation intended to save energy. Same
> >>>> as the limit on water capacity for toilets and the latest washing
> >>>> machines sold in the US. Your government at work.
> >>>>
> >>>>
> >>>> mike hunt
> >>>>
> >>>>
> >>>>
> >>>> "Gary L. Burnore" wrote:
> >>>>>
> >>>>> On Mon, 20 Dec 2004 15:43:59 -0500, Abeness <news@nada.x> wrote:
> >>>>>
> >>>>>> C. E. White wrote:
> >>>>>>> Unfortunately most A/C systems don't run once the
> >>>>>>> temperature drops below 40 degrees Fahrenheit.
> >>>>>>
> >>>>>> I don't believe this holds true for automotive systems. On my
> >>>>>> old Pontiac the A/C was directly tied to the defroster
> >>>>>> setting--switch the system to defrost, and the A/C was
> >>>>>> activated.
> >>>>>
> >>>>> It depends on the make/model. My cressida shuts the A/C off if
> >>>>> you turn the inside temp past 75%.
> >>>>>
> >>>>>> Good way to keep the compressor oils circulating to keep the
> >>>>>> seals lubricated, in addition to removing condensation. Worked
> >>>>>> at any temp, as I recall, and I move around NY/New England.
> >>>>>
> >>>>> It does help with condensation. There's no doubt about that.
> >>>>>
> >>>>>> I'll confirm this on my new 94 Civic in a few days, as it has
> >>>>>> now gotten cold enough around here to check. Disabling it
> >>>>>> below 40 degrees would be idiocy--it's the only way to remove
> >>>>>> condensation effectively.
> >>>>>
> >>>>> I'm pretty sure that even in his case, it's the temp you set the
> >>>>> control to and not the outside temp.
> >>>>>
> >>>>>> It is true, however, that many room A/Cs don't function when
> >>>>>> the outside temp is "too low"--which occasionally annoys me.
> >>>>>
> >>>>> There's a way to fix that, put a plastic bag over the outside
> >>>>> of the A/C after poking several holes in it. (The bag, duh).
>
>

"Abeness" <news@nada.x> wrote in message
news:VOidnRkII9T3glXcRVn-2A@rcn.net...
> Philip wrote:
> > In fact, A/C systems start cycling the compressor at no less than 38
degrees
> > F. SO... when the air coming into the evaporator reaches this low
> > temperature, the compressor is cycled or shut OFF if the air temperature
> > entering the evaporator continues to drop. Otherwise the evaporator
would
> > become a block of ice, which would prevent any air from reaching the
heater
> > core (in nearly all cases).
>
> Now THIS makes perfect sense. (I'd have to look up the temp at which
> refrigerants go liquid to confirm or deny Steve G's belief.) I'm almost
> certain that the A/C on my old 85 Pontiac would cycle at any temp,
> though. I'll check up with the Honda soon.
>
> Anyway, I doubt it would be that difficult (in the original design) to
> construct an airflow system that would shunt warmer air around the evap
> unit when the temp dropped in winter, in order to preserve the
> dehumidifying characteristics of an A/C-based system.

You would also have to direct warm air to the entire low pressure side of
the ac system to prevent the condensing of refrigerant gas back into liquid.
I live in a climate of 10 months of winter and 2 months poor sledding, have
been a licensed mechanic since about '72 and have never seen an ac comp
cycle in ambient temps colder than somewhere around that 40 degree mark.
and remember from my days in tech school that is the reason.
Don't forget when researching boiling point of refrigerant to factor in the
pressure. Adding pressure also raises the boiling point. As I'm typing
this I'm also recalling that there are cautions that when servicing/charging
the system to not allow low side pressure to drop too low for fear of
damaging the compressor. Go to K-mart and look at the labeling/cans of 134a
they market to the consumers and read the instructions. When charging you
override the low side cutout so you can keep the compressor running. In
this situation, temp above ambient cut-out and low pressure limit overidden,
a drop in low side pressure can take it below it's boiling point and risk
liquid refrigerant in the compressor. The warning on the charging kit
doesn't get into the explanation, but does give the caution about low side
pressure drops and damage to the compressor.
Steve

"SoCalMike" <mikein562athotmail@hotmail.com> wrote in message
news:iKUxd.538556$wV.53941@attbi_s54
> MajorDomo@mailcity.com wrote:
>> new model top loading washing machine in the US today.
>
> they still sell top loaders

You have to know that MikeHunt is retired 'gentry' ... who knows little
beyond what his house servants relay to him on this subject.
--

- Philip

"Abeness" <news@nada.x> wrote in message
news:VOidnRkII9T3glXcRVn-2A@rcn.net
> Philip wrote:
>> In fact, A/C systems start cycling the compressor at no less than
>> 38 degrees F. SO... when the air coming into the evaporator
>> reaches this low temperature, the compressor is cycled or shut OFF
>> if the air temperature entering the evaporator continues to drop.
>> Otherwise the evaporator would become a block of ice, which would
>> prevent any air from reaching the heater core (in nearly all
>> cases).
>
> Now THIS makes perfect sense. (I'd have to look up the temp at which
> refrigerants go liquid to confirm or deny Steve G's belief.) I'm
> almost certain that the A/C on my old 85 Pontiac would cycle at any
> temp, though. I'll check up with the Honda soon.
>
> Anyway, I doubt it would be that difficult (in the original design)
> to construct an airflow system that would shunt warmer air around
> the evap unit when the temp dropped in winter, in order to preserve the
> dehumidifying characteristics of an A/C-based system.

Thank you ('perfect sense'). Note that I said "air coming into the
evaporator." If air door is set to FRESH and the inducted air from outside
is below 38-40°F, all one need do (considering all the heat radiating off
the passenger(s), is select RECIRCULATE so that the air inducted to the
evaporator stays above 38-40°F. This will keep the A/C running. Remember
.... once the evaporator effectively become a solid block of ice, there will
be NO dehumidification.
--

- Philip

"Steve G" <NospamforSteve@Steve-Garner.com> wrote in message
news:LRWxd.557009$nl.118459@pd7tw3no
> "Abeness" <news@nada.x> wrote in message
> news:VOidnRkII9T3glXcRVn-2A@rcn.net...
>> Philip wrote:
>>> In fact, A/C systems start cycling the compressor at no less than
>>> 38 degrees F. SO... when the air coming into the evaporator
>>> reaches this low temperature, the compressor is cycled or shut
>>> OFF if the air temperature entering the evaporator continues to
>>> drop. Otherwise the evaporator would become a block of ice,
>>> which would prevent any air from reaching the heater core (in
>>> nearly all cases).
>>
>> Now THIS makes perfect sense. (I'd have to look up the temp at
>> which refrigerants go liquid to confirm or deny Steve G's belief.)
>> I'm almost certain that the A/C on my old 85 Pontiac would cycle
>> at any temp,
>> though. I'll check up with the Honda soon.
>>
>> Anyway, I doubt it would be that difficult (in the original
>> design) to construct an airflow system that would shunt warmer air
>> around the evap unit when the temp dropped in winter, in order to
>> preserve the dehumidifying characteristics of an A/C-based system.
>
> You would also have to direct warm air to the entire low pressure
> side of the ac system to prevent the condensing of refrigerant gas
> back into liquid. I live in a climate of 10 months of winter and 2
> months poor sledding, have been a licensed mechanic since about '72
> and have never seen an ac comp cycle in ambient temps colder than
> somewhere around that 40 degree mark. and remember from my days in
> tech school that is the reason.

Question for you: Water condensation *on* the evaporator surface freezes at
32°F. At what temperature does low pressure refrigerant gas condense to a
solid liquid? Keep in mind that it is common to see frost all over much of
the exiting line from the evaporator leading to the compressor inlet while
the A/C system is functioning normally. Clue: it's lower than 32°F.

> Don't forget when researching boiling point of refrigerant to
> factor in the pressure. Adding pressure also raises the boiling
> point. As I'm typing this I'm also recalling that there are
> cautions that when servicing/charging the system to not allow low
> side pressure to drop too low for fear of damaging the compressor.
snip
>Steve

Not entirely accurate. The compressor's inlet side can drop into a slight
vacuum when a suction throttling valve is used on the outlet side of the
evaporator instead of an expansion valve to regulate refrigerant flow into
the evaporator. In any case, the low side pressure safety switch (if/when
there is one installed) will prevent such a condition from occurring on
systems equipped with only an expansion valve. Excessive high side pressure
is FAR more damaging to compressors which is why a high pressure safety
switch is present on all but the oldest automotive systems.
--

- Philip

"Steve G" <NospamforSteve@Steve-Garner.com> wrote in message
news:nGWxd.538195$Pl.290063@pd7tw1no
> Philip,
> We're talking about two different controls. There are sensors, or
> in older cars, capillary tubes at the evaporators monitoring evap
> temp to control what you're talking about, evaporator icing.

Stop. Evaporator icing prevention has been prevented electrically by
cycling the compressor since I can recall (late '50's). Evaporator icing
prevention has also been prevented mechanically by the use of expansion
valves ... LONG before GM's cheap, clog prone capillary tubes ... by
regulating refrigerant based on expansion valve temperature.

> In late model cars that also cycled the compressor as
> that was how pressure/flow of refrigerant was maintained.

Late model. LOL

> But there is also an
> ambient temp sensor that would not allow the compressor to run
> below a certain outside air temp in order to prevent hydraulic
> lock-up of the compressor due to refrigerant being in a liquid
> state in the comp head.
snip
>Steve

This is false. Evaporator core surface temperature is the primary concern
because the freezing of water condensation on the evaporator/s exterior
surfaces will block air flow. There is never solid liquid refrigerant
condensed in the compressor inlet line, regardless of ambient temperature.
Well... there *could* be if the system were grossly overcharged.
--

- Philip


> "Philip" <1chip-state1@earthlink.net> wrote in message
> news:4nQxd.6785$yK.4838@newsread3.news.atl.earthli nk.net...
>> Has nothing to do with the refrigerant. Has solely to do with the
>> temperature water freezes at ... 32 degrees. Since in most cases,
>> all air flows thru the evaporator and then to or past the heater
>> core, were the water on the evaporator be allowed to freeze solid,
>> no air would flow out of any of the plenum chamber outlets.
>> --
>>
>> - Philip
>>
>> "Steve G" <NospamforSteve@Steve-Garner.com> wrote in message
>> news:0ZOxd.534980$Pl.108826@pd7tw1no
>>> The low temp cutout may have different settings, but that is most
>>> likely a result of the diferent refrigerants used, r12 vs 134a,
>>> Your 83 may still run at 40, but there is a temp close to that
>>> where it will no longer engage. They all had low temp cutouts for
>>> the very reason I mentioned. Or, the low temp cutout may have
>>> been by-passed or is not working properly. Take it out on a cold
>>> frosty morning and run the ac and let us know what happens.
>>> I'm a mechanic by trade (inter-provincially licensed) and worked
>>> in
>>> the field in the 70's and 80's and never saw a compressor cycle in
>>> temp below 35 to 40 F. Up here in the frozen north of Canada we
>>> use our defrost a lot and they would engage the compressor in the
>>> mild weather, but have never seen a compressor run in the cold.
>>> Not sure what it has to do with buying a 3 gal toilet tho...
>>> <MajorDomo@mailcity.com> wrote in message
>>> news:41C78DD7.991EF9E3@mailcity.com...
>>>> You certainly are entitle to your own opinion. The AC on my 83
>>>> Continental will run below 40 degrees but not my 2005 Lincoln LS
>>>> or my 2003 Mustang GT. Go try a buy a three gallon toilet or a
>>>> new model top loading washing machine in the US today.
>>>>
>>>>
>>>> mike hunt
>>>>
>>>>
>>>>
>>>> Steve G wrote:
>>>>>
>>>>> No it's not!
>>>>> AC systems have always had low temp cutouts on them, and it's
>>>>> not idiocy for the above poster. The ac is called for anytime
>>>>> the defrost is selected on most cars but is prevented from
>>>>> cutting in below 40 F because below that temp the gaseous
>>>>> refrigerant will liquefy and as we all know you can not
>>>>> compress a liquid. It
>>>>> cuts it out so that your compressor doesn't smash to little bits
>>>>> trying to compress liquid refrigerant.
>>>>> Short lesson in refrigeration, compressor draws in low pressure
>>>>> gas, pumps out high pressure gas. High pressure gas condenses
>>>>> into a liquid under pressure in... what else but the condenser
>>>>> (that other rad in the front of your car). High pressure liquid
>>>>> is metered/sprayed into the evaporator where it becomes a low
>>>>> pressure gas again and so on.
>>>>>
>>>>> For the OP, cars with persistant high humidity situations
>>>>> sometimes have water leaks that may not be apparent. I had a
>>>>> Supra that leaked water
>>> at
>>>>> the hatch. Windows seemed to fog easily. Discovered one day
>>>>> that the spare tire well was half full of water.
>>>>> Steve
>>>>> <MajorDomo@mailcity.com> wrote in message
>>>>> news:41C78298.78A50057@mailcity.com...
>>>>>> The deactivation on newer domestic and automotive AC's, at 40
>>>>>> degrees, is a federal regulation intended to save energy. Same
>>>>>> as the limit on water capacity for toilets and the latest
>>>>>> washing machines sold in the US. Your government at work.
>>>>>>
>>>>>>
>>>>>> mike hunt
>>>>>>
>>>>>>
>>>>>>
>>>>>> "Gary L. Burnore" wrote:
>>>>>>>
>>>>>>> On Mon, 20 Dec 2004 15:43:59 -0500, Abeness <news@nada.x>
>>>>>>> wrote:
>>>>>>>
>>>>>>>> C. E. White wrote:
>>>>>>>>> Unfortunately most A/C systems don't run once the
>>>>>>>>> temperature drops below 40 degrees Fahrenheit.
>>>>>>>>
>>>>>>>> I don't believe this holds true for automotive systems. On my
>>>>>>>> old Pontiac the A/C was directly tied to the defroster
>>>>>>>> setting--switch the system to defrost, and the A/C was
>>>>>>>> activated.
>>>>>>>
>>>>>>> It depends on the make/model. My cressida shuts the A/C off
>>>>>>> if
>>>>>>> you turn the inside temp past 75%.
>>>>>>>
>>>>>>>> Good way to keep the compressor oils circulating to keep the
>>>>>>>> seals lubricated, in addition to removing condensation.
>>>>>>>> Worked
>>>>>>>> at any temp, as I recall, and I move around NY/New England.
>>>>>>>
>>>>>>> It does help with condensation. There's no doubt about that.
>>>>>>>
>>>>>>>> I'll confirm this on my new 94 Civic in a few days, as it has
>>>>>>>> now gotten cold enough around here to check. Disabling it
>>>>>>>> below 40 degrees would be idiocy--it's the only way to remove
>>>>>>>> condensation effectively.
>>>>>>>
>>>>>>> I'm pretty sure that even in his case, it's the temp you set
>>>>>>> the control to and not the outside temp.
>>>>>>>
>>>>>>>> It is true, however, that many room A/Cs don't function when
>>>>>>>> the outside temp is "too low"--which occasionally annoys me.
>>>>>>>
>>>>>>> There's a way to fix that, put a plastic bag over the outside
>>>>>>> of the A/C after poking several holes in it. (The bag, duh).
>>>>>>>

Why do you always seem to find it necessary to stoop to personal
assaults? Have I ever personally attacked you or anyone in a
NG? I would suggest you do some research before you choose to
comment on a subject of which you obviously are not fully
informed, or at least say in my opinion

One can still buy Freon, as well, but it can not be
manufactured.



mike hunt



Philip wrote:
>
> "SoCalMike" <mikein562athotmail@hotmail.com> wrote in message
> news:iKUxd.538556$wV.53941@attbi_s54
> > MajorDomo@mailcity.com wrote:
> >> new model top loading washing machine in the US today.
> >
> > they still sell top loaders
>
> You have to know that MikeHunt is retired 'gentry' ... who knows little
> beyond what his house servants relay to him on this subject.
> --
>
> - Philip

Mike ... you have always hinted around at your wealth on this and several
other forums. Don't even try ... to go humble on me. LOL If you
interpreted my comment as a negative, send me a check sufficient to remove
that discomfort for being "gentry". ;-)

There are plenty of appliance outlets including Sears that sell NEW top
loaders today. And so long as the price of a front loader is relatively
high, politics (poor people disproportionately affected) will delay your
notion ... or there will be a government subsidy. LOL
--

- Philip

<BigJohnson@mailcity.com> wrote in message
news:41C85A90.453F210F@mailcity.com
> Why do you always seem to find it necessary to stoop to personal
> assaults? Have I ever personally attacked you or anyone in a
> NG? I would suggest you do some research before you choose to
> comment on a subject of which you obviously are not fully
> informed, or at least say in my opinion
>
> One can still buy Freon, as well, but it can not be
> manufactured.
>
>
>
> mike hunt
>
>
>
> Philip wrote:
>>
>> "SoCalMike" <mikein562athotmail@hotmail.com> wrote in message
>> news:iKUxd.538556$wV.53941@attbi_s54
>>> MajorDomo@mailcity.com wrote:
>>>> new model top loading washing machine in the US today.
>>>
>>> they still sell top loaders
>>
>> You have to know that MikeHunt is retired 'gentry' ... who knows
>> little beyond what his house servants relay to him on this subject.
>> --
>>
>> - Philip

Why does a glass of Ice water condensate in the Summer? Same reason your
windows fog up. Turning on the A/C in conjunction with the heater will help
dissipate the fog. The A/C puts out a dryer air than just the heater alone.
The heater will eventually dry up the fog, but it takes a while since it
depends on the coolant in your engine for heat. It's also a good thing to
run the A/C in the winter to stir up the coolant.

Don't have A/C? Then you're SOL, just kidding. Buy Rain-X Anti-Fog or that
pink wax stick you see at the home shows, and wipe it on your inside
windows. I rub the pink stuff on a terry shop towel and keep it under the
seat of all my cars for that purpose. Don't wipe your windows while
driving, pull over to a safe place and stop before wiping your windows.

Good Luck and Safe Driving!
JW

"ajpdla" <ajpdla@pacifier.com> wrote in message
news:10se14ls3l7qt3b@corp.supernews.com...
> Condensation on the inside windows. I hate it. How do I get rid of it?
> What's the cause of it? Why does it take so long to remove with the
> defroster? How can I seal up the outside of my car. What's the best way
to
> check for air/water infiltration. Ugh. Help!
>
>

Can I have a check, too? I could use a new front loader.

Aaron

"Philip" <1chip-state1@earthlink.net> wrote in message
news:q6Zxd.7952$yK.7521@newsread3.news.atl.earthli nk.net...

> send me a check