"Abeness" <news@nada.x> wrote in message
news:Qf6dnRCLjPwQpFrcRVn-3w@rcn.net
> 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.

It does apply to automotive A/C.

>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. 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.
>
> 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. It is true, however, that many room A/Cs don't
> function when the outside temp is "too low"--which occasionally
> annoys me.

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).

--

- Philip