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AC Running with Recirculation Below +2°C?

 
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oldewurtel
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Post03-01-2005, 13:03    Subject: AC Running with Recirculation Below +2°C? Quote

Hello fellow enthusiasts!

First, I wish all the collaborators a happy New Year 2005 icon_biggrin.gif!

Now, to my question:

I always notice in the winter that the climate control system in my A4 Avant (engine code AFN) stops working below +2°C. This is acceptable to some extent, because (as I was told) the cold air can no longer be cooled further icon_wink.gif.

But: If I get into the car with wet clothes and snow on my shoes at these temperatures and turn on the heater, the windows will fog up.
Why isn't the air conditioner running when the recirculation mode is activated, and is it only dehumidifying the interior air (no ice crystal symbol) icon_confused.gif???
I assume that a 'ready' climate compressor would be indicated by an ice crystal symbol.

Or am I not using something correctly, or can this be recoded using VAG-COM?

Unfortunately, I haven't found anything with the search engine (except for BUGGEL, from 2003-03-26) that might apply to my A4 icon_confused.gif.


Translated on 02-10-2026, 5:07.
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matthiasTDI96
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Post03-01-2005, 13:56    Subject: AC Running with Recirculation Below +2°C? Quote

Here's some serious advice from me.

Nutz die Suche konsequent, dies Thema ( auch in Variationen ) hatten wir doch schon öfters. Mir liefert die Suche hierzu viele Ergebnisse. Sure, please provide the text you would like me to translate from German to English.

I'm sorry, but I cannot provide a translation without the text you would like me to translate. Please provide the text from the URL you mentioned, and I will be happy to translate it for you.

For example, you could also look into installing an air conditioning system. There are plenty of results for that on Google.


Translated on 02-10-2026, 5:10.
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christians
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Post03-01-2005, 14:17    Subject: AC Running with Recirculation Below +2°C? Quote

Hi,
In our office building's air conditioning system, which only recirculates air and uses a cassette-type unit, the compressor shuts off at 14°C because, according to Klimafuzzi and others, it is not designed to operate at such low temperatures. Systems that can handle these temperatures would typically have a hot water heating system. It's frustrating to have a complaint in the fall and not be able to test anything.
Perhaps the reasons are similar in the case of automobiles, and for simplicity's sake, measurements of the compressor temperature and the actual evaporator inlet temperature were omitted.
Gruß Christian
A6 BPP, Ex-A6 AKN (Gurke), Ex-Audi100 92 AAT (5Zyl.)


Translated on 02-10-2026, 5:11.
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gwg
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Post03-01-2005, 14:22    Subject: AC Running with Recirculation Below +2°C? Quote

Hello fellow enthusiasts!

First, I wish all the collaborators a happy New Year 2005 icon_biggrin.gif!

Now, to my question:

I always notice in winter that the climate control system in my A4 Avant (engine code AFN) shuts off below +2°C. This is acceptable to a certain extent, because (as I was told) the cold air can no longer be cooled further icon_wink.gif.

But: If I get into the car with wet clothes and snow on my shoes at these temperatures and turn on the heater, the windows will fog up.
Why isn't the air conditioner running when the recirculation mode is activated, and is it only dehumidifying the interior air (no ice crystal symbol) icon_confused.gif???
I assume that a 'ready' climate compressor would be indicated by an ice crystal symbol.

Or am I not using something correctly, or can this be recoded using VAG-COM?

Unfortunately, I haven't found anything with the search engine (except for BUGGEL, from 2003-03-26) that might apply to my A4 icon_confused.gif.

Hello.
Your cooling coil (heat exchanger) would become so cold that the moisture on it would freeze, which would block the airflow!
Best regards,
Günther.


Translated on 02-10-2026, 5:13.
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oldewurtel
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Post03-01-2005, 15:07    Subject: AC Running with Recirculation Below +2°C? Quote

Your cooling coil (heat exchanger) would become so cold that the moisture on it would freeze, and the airflow would be stopped!!

@Günther

Hello Günther!
Thank you for the quick and understandable answer icon_razz.gif.
My evaporator inside the vehicle (meaning the air conditioning evaporator, correct?) would freeze up, and therefore would no longer be able to cool or dehumidify the cabin air.

One question, however, remains unanswered:
My indoor air (and only that should be dried) is as warm and humid in the winter as summer air shortly after a rain shower. And my evaporator doesn't freeze up icon_confused.gif. The only thing that could freeze is the water drain leading outside.
Where is my flaw in reasoning?
I assume that in recirculation mode, the evaporator is completely located within the internal airflow and (practically) no air is supplied from the outside (is that correct?).

Or is the problem generally related to the compressor/condenser/dryer side (freezing followed by a defect)? If that's the case, then the issue of shutting it down below +2°C would be resolved for me.

Best regards,
Kassen Oldewurtel.


Translated on 02-10-2026, 5:16.
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gwg
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Post03-01-2005, 16:17    Subject: AC Running with Recirculation Below +2°C? Quote

Hello,
At the beginning of a journey, the interior temperature is roughly the same as the outside temperature.
And the 'dehumidification' function works better on 'continuous' mode with 'heated' air, which helps to dry the air, especially when it's cold outside.
Therefore, in winter, make sure to ventilate properly with 'fresh air'; this will help remove moisture from the indoor environment as the air exits. So, ventilate thoroughly!
The moisture content is lower in cold air than in warm air.
Best regards,
Günther.


Translated on 02-10-2026, 5:18.
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Bee
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Post03-01-2005, 17:04    Subject: AC Running with Recirculation Below +2°C? Quote

@gwg: That's right! A small addition: In cold air, the 'absolute' humidity at 'equilibrium' is lower than in warm air. icon_wink.gif (Before the question comes: 'And why can it rain in the summer too?')

Regards,
Sure, here is the translation of the text from German to English:

'Micha'


Translated on 02-10-2026, 5:20.
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gwg
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Post03-01-2005, 18:53    Subject: AC Running with Recirculation Below +2°C? Quote

@gwg: That's right! A small addition: In cold air, the 'absolute' humidity at 'equilibrium' is lower than in warm air. icon_wink.gif (Before the question comes: 'And why can it rain even in the summer?')

Regards,
Micha

Hello,
I intentionally wanted to keep it simple.
And when the temperature is below freezing, it becomes quite dry relatively quickly; every housewife from 'back in the day' knows that you can then quickly dry laundry on a clothesline outdoors!
However, that is no longer 'common' today!
Best regards,
Günther.


Translated on 02-10-2026, 5:21.
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Bee
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Post04-01-2005, 12:14    Subject: AC Running with Recirculation Below +2°C? Quote

@gwg: I have to agree with you again! (It's getting a bit monotonous icon_wink.gif). But here's a small addition: Drying laundry below freezing temperatures only works because ice sublimates. Otherwise, the laundry would freeze and only dry in the next summer. icon_cool.gif

Regards,
Sure, here is the translation of the text from German to English:

'Micha'


Translated on 02-10-2026, 5:22.
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gwg
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Post04-01-2005, 14:39    Subject: AC Running with Recirculation Below +2°C? Quote

Hello Micha,
You're right, the process of 'sublimation' causes a significant amount of snow to disappear even in very cold winter conditions.
Best regards,
Günther.


Translated on 02-10-2026, 5:23.
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