Ac Operation In Cold Weather!

[darton]

Apparently the air con will not operate below 6 degrees C, I have found this mentioned somewhere on the site.

first thing, Is this correct?

if so, is there a good reason for this? my partners Toyota AC works no matter what the external temp. Driving the car in cold conditions is very difficult with no air con to clear the windows, it steams up like a Turkish bath!. The standard venting is woefully inadequate in a car this size, just leaves me with a small hole through the condensation near the mirrors.

If there is an outside temp sensor that cuts off the air con operation at 6 degrees, can it be disconnected? if so would this be detrimental in any way?

Hope someone can help as winter is on its way again! Thanks..Neil ;)

Edited October 19, 2009 by darton

[big_kev]

Apparently the air con will not operate below 6 degrees C, I have found this mentioned somewhere on the site.

first thing, Is this correct?

 

I believe the figure is either 5 or 10 degrees dependant upon the model.

 

Can't think why you would want to blow cold air below this temperature.

[jkspoff]

My A/C is very useful in winter to blow dry air throughout the car and keep it dehumidified, preventing the cars interior from steaming up, so it does still work with the heaters for this very reason. Especially when a family full of people get in from the pouring rain.

[gregers]

plus as mentioned many times,that its best to use the aircon to clear the screen quicker then the normal heater,and using the aircon in the winter months keeps the whole system working correctly.

[big_kev]

I believe the figure is either 5 or 10 degrees dependant upon the model.

 

Apologies.....I'm talking rubbish....again !

 

These figures are for the booster heater......it was on my mind at the time.

 

 

Please ignore me !

 

I will go away now and hang my head in shame.. ;)

[gregers]

so you should,

 

STUPID BOY PIKE.

[big_kev]

Sorry, Captain Mainwaring... ;)

[darton]

Thanks for the help guys, and yes it is for the drying effect of the aircon not the cooling side of it,but still need some more stats on the actual operation of the system because i do not want to bugger it up altogether trying to make it work below 6C! ;) any more info very welcome cheers!..

[Mirez]

Ford A/C systems typically shut down at around 4*c which is to prevent the evaporator from freezing up, I would guess the galaxy system is VW spec'ed but it would probably still be around this temperature.

[Mirez]

Ford A/C systems typically shut down at around 4*c which is to prevent the evaporator from freezing up, I would guess the galaxy system is VW spec'ed but it would probably still be around this temperature.

 

VW Spec appears not to be quite so specific! A/C should switch off when ambient temperatures are below approximately 5*c.

[darton]

Ford A/C systems typically shut down at around 4*c which is to prevent the evaporator from freezing up, I would guess the galaxy system is VW spec'ed but it would probably still be around this temperature.

 

VW Spec appears not to be quite so specific! A/C should switch off when ambient temperatures are below approximately 5*c.

 

Thanks Mirez,.do you know any way of making it operate below this temp or is that it? cheers

[gregers]

probably by trying to fool the temp sensor,maybe ?

[big_kev]

You guys are aware that the drying effect only happens when the aircon is blowing out very cold air.

 

It doesn't work when the heater is on.

[tim-spam]

Talking rubbish again. It works very well for demisting even on cold days when the heater is being used.

As for fooling the system into working below 5 degC, don't try, because if you do, you run the very real danger of icing up the evaporator and causing severe damage. All systems on whatever make of car will not work below a certain temperature, which typically varies from 2 degC to 6 degC depending on the make and model of car.

[Mirez]

Thanks Mirez,.do you know any way of making it operate below this temp or is that it? cheers

 

Only by changing the sensor for a different one or fooling it with a resistance change. Dropping the temperature it turns off at though could be dangerous - its there to protect the system from icing up and if you get ice in the system which reaches the compressor then it'll be game over as you can only compress gas not liquids or solids. You could probably safely drop the temperature by a few degrees and get away with it.

 

If you're still feeling brave and fancy a fiddle then you might find this topic interesting to read: AC Mod Its from a forum I used to belong to some years back. The principle would be the same however the values would need to be investigated.

 

Kev, the A/C should work at demisting regardless of temperature selected- its effect will be marginally better when its blowing cold air as opposed to hot but the drying effect remains.

[big_kev]

Talking rubbish again. It works very well for demisting even on cold days when the heater is being used.

 

As the drying operation works by the temperature control being set to cold (colder than the cabin air temperature) and the air is diverted past the evaporator and the water vapour is condensed out of the air onto the cold evaporater.

 

Please explain how this works when the temperature control is set to hot (hotter than the cabin temperature) and the air is no longer hitting the evaporater but is diverted past the heater matrix instead.

 

 

 

In your own time !

[darton]

Thanks for all the input guys,as a general consensus, it seems I'd best leave it alone so as not to bust it altogether! It is a little infuriating though with a car full of people and they are all irritatingly wiping the windows with the back of their hands, just makes me think, its supposed to be the 21st century and where no further ahead in demisting than my 1970s ford Cortina!! never mind ;)

[tim-spam]

Please explain how this works when the temperature control is set to hot (hotter than the cabin temperature) and the air is no longer hitting the evaporater but is diverted past the heater matrix instead.

Firstly, if you have aircon, try it and see - it works - fact.

 

Secondly, when the temperature control is set to 'hot', the air still passes through the evaporator before passing through the heater matrix, which is why it works. Simple!

[big_kev]

when the temperature control is set to 'hot', the air still passes through the evaporator before passing through the heater matrix, which is why it works. Simple!

 

No it doesn't...even simpler.

[Mirez]

No it doesn't...even simpler.

 

Sorry Kev but you are mistaken, regardless of temperature position if the A/C is swiched on (and working on the galaxy lol) then the evaporator will remove moisture from the air.

[big_kev]

Nah !

 

 

However I will investigate this futher in case I am mistaken.

 

(again.....! )

[darton]

Not sure who may be right here,but I do know when mine does work, I set it to warm and fast fan.. and no more mist ! don't know if it works when set high to hot, never found it necessary! thanks chaps :o

[tim-spam]

However I will investigate this futher in case I am mistaken.

 

(again.....! )

No need - we've already told you how it works, so why argue??

[big_kev]

No need - we've already told you how it works, so why argue??

 

Because I am correct ?

[tim-spam]

Why do you do this? Everyone with aircon knows you're wrong.

 

Just think for a minute - aircon can be used very effectively to demist the windows, even in cooler weather, so why on earth would a car design engineer design a system which shut this facility off when using the heater. Answer: he wouldn't.

 

Now, 2 of my cars have aircon, and I use it very effectively for de-misting the windows, even on days like today (raining, 10 degC, misted windows this morning). Heater fully on, switch aircon on and windows clear within seconds (not several minutes). When the temperature drops to below 5 degC, it is a real pain because misted windows can take ages to clear - why do you think this thread was started in the first place?? (Clue: perhaps because Neil, like many others, uses his aircon to demist the windows, even in cold weather with the heating on).

 

This thread is beginning to remind me of one concerning torque figures a while ago.....

 

However, if you wish to persist in your own ill-conceived belief in the face of all reasonable explanation and the facts themselves, then I suppose that there is little any of us can do except point out the facts for the benefit of those who are seeking real information.