Air Con question..

[Zaul]

Ok first the disclaimer: I didn't a search of forum and couldn't find one along these lines, but if I have transgressed please give me my penance and merge this with the appropriate thread.

Now that's out of the way..I have a question about the heater/ac in my MkVI GTI.

Ever since I got it (in June) I've had the heater set to auto, 22 degrees and was able to then alter the vents being used between dash, feet, windscreen etc. In doing this the settings would stay on auto.

But about a week ago after turning it off one day I find I can't put the AUTO switch on WITHOUT the a/c coming on.

I have read the manual but can't find anyway to get it back to my preferred settings.

Can anyone help please?

[moniker]

I think hitting auto causes the A/C light to come on and stay on even when the temp is changed (does not mean the A/C compressor is running it just means it can) if you hit the A/C button it will turn off and stay off. I'm not sure I understand the question fully. Can't put the auto on without the A/C light coming on? Normal I think. A/C coming on when altering to feet etc.? Not normal.

[AdamD]

But about a week ago after turning it off one day I find I can't put the AUTO switch on WITHOUT the a/c coming on.

I don't have my car or the manual in front of me, but I believe the AUTO button has two settings (and two lights) - press it once and it goes into one mode, press it again and it enters another. Maybe you need to press it twice and make sure the righthand light is illuminated.

If I have time I'll update this post tonight once I've double-checked the manual.

[Ryan_R]

Pressing Auto the second time just turns the fan speed up more to reach the temperature quicker. I thought every new car with an 'Auto' setting kept the A/C on - usually to keep the front windscreen from fogging up. The A/C won't run if you're asking for heat (I'm sure the Germans know what they're doing)

[pologti18t]

Pressing Auto the second time just turns the fan speed up more to reach the temperature quicker. I thought every new car with an 'Auto' setting kept the A/C on - usually to keep the front windscreen from fogging up. The A/C won't run if you're asking for heat (I'm sure the Germans know what they're doing)

Of course the A/C and heat can be used together. Its a mixer system that mixes chilled A/C air with air thats passed through the heater matrix. Otherwise how would it hold the temp at a steady temp.

[Zaul]

Yep, if the left hand side of the AUTO button was illuminated then the AC would be off, press it again and the AC pops on.

But, and here's where it gets confusing, with the LEFT hand side of the AUTO button lit when I pushed one of the vent buttons to have the air blowing onto the window, or my feet, or just through the the dash the AC would come on. When I first got the car this didn't happen. I could change the vents without the AC being activated. Nice 22 degrees.

For a few weeks changing the vent buttons didn't make the AC come on and I've no idea if I"m doing something different or pressed something somehere. If I don't have to use the AC to heat, (and hence the additional petrol) I'd rather not.

I guess I'm wondering why it suddenly changed settings? I didn't do anything differently.

[slipshot]

Yep, if the left hand side of the AUTO button was illuminated then the AC would be off, press it again and the AC pops on.

But, and here's where it gets confusing, with the LEFT hand side of the AUTO button lit when I pushed one of the vent buttons to have the air blowing onto the window, or my feet, or just through the the dash the AC would come on. When I first got the car this didn't happen. I could change the vents without the AC being activated. Nice 22 degrees.

For a few weeks changing the vent buttons didn't make the AC come on and I've no idea if I"m doing something different or pressed something somehere. If I don't have to use the AC to heat, (and hence the additional petrol) I'd rather not.

I guess I'm wondering why it suddenly changed settings? I didn't do anything differently.

You don't have to use the AC to heat - the heat being dependant upon the water sloshing round the engine and heating up when the car is cold. However, it's better to have the AC on when using the heat as it helps remove the moisture etc from the air. That's why, should you hit the quick demist button the AC will turn on. That's also why you see cars with misted up windows on wet days sine they either do not have AC or they have the AC off. AC will remove this moisture and thus help keep your windows clear of condensation.

Plus just because the AC Light is on does not mean the AC unit is always working. As others have said, it will turn itself on and off as and when required. If you want to save fuel, just adopt your driving style since that will have a bigger effect.

I remember reading a study about AC and the effect on economy and the study showed that having the AC on in a car versus the AC Off, but the windows open actually mean the car was more efficient with the AC on, because the car caused so much additional drag with windows open compared to the AC being on. Of course every car is different, but it was interesting none the less. AC compressors etc are pretty damn good these days...

[Maverick]

Plus just because the AC Light is on does not mean the AC unit is always working. As others have said, it will turn itself on and off as and when required. If you want to save fuel, just adopt your driving style since that will have a bigger effect.

Actually the AC compressor is NEVER turned off and is always in operation, it's variable controlled however and can operate from as little as 2% up to 100%.

Sanden PXE16 Air Conditioner Compressor Specifications (1K0820803)

I remember reading a study about AC and the effect on economy and the study showed that having the AC on in a car versus the AC Off, but the windows open actually mean the car was more efficient with the AC on, because the car caused so much additional drag with windows open compared to the AC being on. Of course every car is different, but it was interesting none the less. AC compressors etc are pretty damn good these days...

Exactly and especially with full climate control, just leave the unit to itself and it'll maintain a constant pressure. Stuffing around all the time does nothing except waste time, cause the unit to operate harder and take the drivers attention off driving.

[MkVIGTI]

Yep, if the left hand side of the AUTO button was illuminated then the AC would be off, press it again and the AC pops on.

But, and here's where it gets confusing, with the LEFT hand side of the AUTO button lit when I pushed one of the vent buttons to have the air blowing onto the window, or my feet, or just through the the dash the AC would come on. When I first got the car this didn't happen. I could change the vents without the AC being activated. Nice 22 degrees.

For a few weeks changing the vent buttons didn't make the AC come on and I've no idea if I"m doing something different or pressed something somehere. If I don't have to use the AC to heat, (and hence the additional petrol) I'd rather not.

I guess I'm wondering why it suddenly changed settings? I didn't do anything differently.

If you leave it in auto, it will automatically choose where to distribute the airflow. But that's why the auto light goes off when you manually choose where to distribute the air coming out.

[cameronp]

Ok first the disclaimer: I didn't a search of forum and couldn't find one along these lines, but if I have transgressed please give me my penance and merge this with the appropriate thread.

Now that's out of the way..I have a question about the heater/ac in my MkVI GTI.

Ever since I got it (in June) I've had the heater set to auto, 22 degrees and was able to then alter the vents being used between dash, feet, windscreen etc. In doing this the settings would stay on auto.

But about a week ago after turning it off one day I find I can't put the AUTO switch on WITHOUT the a/c coming on.

I have read the manual but can't find anyway to get it back to my preferred settings.

Can anyone help please?

In my Golf, pressing the AUTO button will always turn the air conditioner on. It is then possible to switch the air con off, and it will remain on auto. Adjusting the fan speed or the vents will switch AUTO off. I can't remember if switching all of the individual vent switches off will put it back in AUTO mode again or not - have a vague feeling it will, but not switch the AC back on.

Having the AC on when it's cold outside appears to make no difference to fuel consumption (measured when idling at traffic lights - stays at 0.6 - 0.7 L/hour) but does an excellent job of stopping the windows from fogging up.