Question on heating & cooling/AC

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Sat 19 May 2007 17:02
Question on heating & cooling/AC - movilogo
I have a question on how heating and cooling works on the cars.

Usually, I see following 3 dials on most cars

First - with blue and hot marking to set hot/cold air flow
Second - dial with position of air flow [face/leg/front etc.]
Third - 0 1 2 3 4 etc. marking for blower

Then a separate switch for AC.

Now even with non-AC cars, the 3 dials are usually present.
Then what is the actual function of AC switch?

How does AC function differs from non-AC car with first dial in blue (cool) zone?

Thanx
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Sat 19 May 2007 17:04
Question on heating & cooling/AC - mss1tw
A/C cools the air to below ambient temperature and de-humidifies it as well.

Non A/C just blows air at you.
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Sat 19 May 2007 17:54
Question on heating & cooling/AC - L'escargot
A/C ............ de-humidifies it ...........


Not as a design intention. It's just that the cooling coils are cold enough for moisture to condense on them.
--
L\'escargot.
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Sat 19 May 2007 18:01
Question on heating & cooling/AC - mss1tw
Not as a design intention. It's just that the cooling coils are cold enough for
moisture to condense on them.


From the FAQ's

A service and a new accumulator/dryer costs around £150 + VAT. Some a/c specialists argue that this needs to be done otherwise the silica gel desiccant in the dryer could break up and circulate through the system, severely damaging it.
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Sat 19 May 2007 18:26
Question on heating & cooling/AC - Westpig
an awful lot of people don't seem to realise that air con can come out hot or warm... and not just cold
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Sat 19 May 2007 22:47
Question on heating & cooling/AC - bristolmotorspeedway {P}
an awful lot of people don't seem to realise that air con can come out
hot or warm... and not just cold

Yep, the number of people I know who, even though they have air-con, have never discovered this, or it's demisting abilities.
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Sat 19 May 2007 20:04
Question on heating & cooling/AC - Number_Cruncher
>>the silica gel desiccant in the dryer could break up

Yes, that's to take moisture out of the refrigerant that cycles round and round in the AC system - not the air that is blown into the car.

Number_Cruncher
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Sat 19 May 2007 20:04
Question on heating & cooling/AC - mss1tw
Ah OK, i didn't know that.
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Sat 19 May 2007 20:10
Question on heating & cooling/AC - Aprilia
A/C is complete refridgeration system installed in the car and powered from the engine. The A/C switch turns on the system (actually enagages an engine-drivern compressor which drives the system). Heat is 'pumped' from an evaporator inside the car (which gets cold) to a condensor at the front of the car (which gets hot).

The evaporator cools (to a minimum of about 4 deg. C) and hence dehumidifies the incoming air. It then passes over the heater radiator which warms it back up to the desired temp you set on the temp adjuster control. So you get dehumidified air, which you can adjust to a temperature of your choice.
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Sat 19 May 2007 23:20
Question on heating & cooling/AC - hxj

I understood that was exactly the intention - hence the name 'Air Conditioning'
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