Aircon always on?

[mike sel]

Whereas having the a/c on is great for demisting, I find that there’s a tendency for the windows to mist up even more when the Engine is off and car stationery requiring even more demisting next time round. I try and manage without using A/C where I can and only use it when the none a/c venting is unable to clear the screen.

I suppose a great case for the heated windscreen option.

[Andy Beats]

When I had the Citroen C3 on loan my lips got so dry they were bleeding and quite painful due I think to the air con.

God, I wish the aircon in the Polo was as effective.
I'm not convinced it works at all at low temperatures.
The aircon light is on, but the woeful demisting suggests the aircon isn't dehumdifying.
Others cars with aircon will clear a misty windscreen in seconds, literally seconds.
The Polo doesn't do this, which suggests it's just acting as a normal heater and no dehumdifying taking place at all.

[roywolfey]

The manual mentions that the cooling system functions only when the engine is running and at ambient temperatures above +3 degrees C

It also states that with manual air conditioning the Defrost function is activated by setting the rotary knob to the 12 Oclock Windscreen position and that when the defrost function is switched on, it is not possible to switch the air recirculation mode on or the air conditioning compressor off.

It also mentions that the following three situation override the Start/Stop function:

The central (fan speed) rotary know is set to 3 or higher, AND the left rotary know is turned as hot as possible AND the right one set to Windscreen, or the left rotary knob is set as cold as possible, the right know is not turned to windscreen, and recirculation mode is switched on.

[Andy Beats]

The manual mentions that the cooling system functions only when the engine is running and at ambient temperatures above +3 degrees C

It also states that with manual air conditioning the Defrost function is activated by setting the rotary knob to the 12 Oclock Windscreen position and that when the defrost function is switched on, it is not possible to switch the air recirculation mode on or the air conditioning compressor off.

It also mentions that the following three situation override the Start/Stop function:

The central (fan speed) rotary know is set to 3 or higher, AND the left rotary know is turned as hot as possible AND the right one set to Windscreen, or the left rotary knob is set as cold as possible, the right know is not turned to windscreen, and recirculation mode is switched on.

I understand no cooling function below a certain temperature.
But what is it doing when the aircon light comes on?
As I said, other cars still use their aircon to dehumidify the car, the Polo doesn't appear to do this, the demisting is no better than a car with no aircon at all.
So I can only assume the aircon is, literally, a con.....

[roywolfey]

The manual mentions that the cooling system functions only when the engine is running and at ambient temperatures above +3 degrees C

It also states that with manual air conditioning the Defrost function is activated by setting the rotary knob to the 12 Oclock Windscreen position and that when the defrost function is switched on, it is not possible to switch the air recirculation mode on or the air conditioning compressor off.

It also mentions that the following three situation override the Start/Stop function:

The central (fan speed) rotary know is set to 3 or higher, AND the left rotary know is turned as hot as possible AND the right one set to Windscreen, or the left rotary knob is set as cold as possible, the right know is not turned to windscreen, and recirculation mode is switched on.

I understand no cooling function below a certain temperature.
But what is it doing when the aircon light comes on?
As I said, other cars still use their aircon to dehumidify the car, the Polo doesn't appear to do this, the demisting is no better than a car with no aircon at all.
So I can only assume the aircon is, literally, a con.....

I can't say for sure but I can only assume that the dehumidifying function also does not work at ambient temperatures below 3 degrees C. I don't think that this is too uncommon as I've had other cars not dehumidify below certain temperatures. Maybe it's due to the risk of the pipe that expels the extracted water freezing up.

[Andy Beats]

I can't say for sure but I can only assume that the dehumidifying function also does not work at ambient temperatures below 3 degrees C. I don't think that this is too uncommon as I've had other cars not dehumidify below certain temperatures. Maybe it's due to the risk of the pipe that expels the extracted water freezing up.

I've literally not had any car where the dehumidifying stops working below a certain temperature.
This is umpteen different makes of cars.
It's not as if I'm just assuming it's working, as it's very easy to tell the difference in demist whether it's on or not.
So you would say it's safe to assume that below a temperature in the Polo, the aircon is just a random light with no function at all....just 'a light'...?
God this car is starting to really p*** me off.

EDIT - even my Leaf aircon dehumidifying function worked at low temperatures, and it had no engine heat for any pipes to defrost.

[monkeyhanger]

The manual mentions that the cooling system functions only when the engine is running and at ambient temperatures above +3 degrees C

It also states that with manual air conditioning the Defrost function is activated by setting the rotary knob to the 12 Oclock Windscreen position and that when the defrost function is switched on, it is not possible to switch the air recirculation mode on or the air conditioning compressor off.

It also mentions that the following three situation override the Start/Stop function:

The central (fan speed) rotary know is set to 3 or higher, AND the left rotary know is turned as hot as possible AND the right one set to Windscreen, or the left rotary knob is set as cold as possible, the right know is not turned to windscreen, and recirculation mode is switched on.

Today I noticed that setting blower to Windscreen only did not have the aircon on, but ambient temp was 1C. So that 3C ruleobviously kicking in. It didn't start using aircon when I turned the temp up while winscreen only venting was on.

I put the car into windscreen/down venting and my feet were getting cold. So I put it into front venting. Misting started quite quickly, but by closing almost all of the front facing vents, a lot of air is then diverted to the screen and stops misting. I did have all front facing vents closed, but the one nearest drivers door on the dash then whistled- so I opened it up.

Despite no covert aircon activity by the car, my mpg was as poor as always, but the car hadn't been used all weekend (for once), so I suspect the alternator was working overtime to charge the battery after the dashcams drain on it. The battery was a decent 14.2v by the time I got to work, but the stop start had not been available the whole journey.

[monkeyhanger]

So the drive home was better than normal (congestion consistent with a good drive to work). Kept an eye on aircon usage in convenuence consumers, negligible shown amounts. Ambient was 3.5C most of the way home and a few flits into windscreen venting only saw aircon not coming on. When temp crept to 4C aircon use was up again when I briefly selected windscreen venting only (confirming the 3C cut-off for aircon).

So decent lack of congestion, negligible compulsory aircon, and still only 34.8mpg. The stop-start was unavailable again, suggesting high alternator load to charge the battery again, but battery was still a healthy 14.2v as it was at the end of my commute to work this morning.

Either the convenience consumers indicator of consumption massively overstates usage, or my dashcam gobbled up about 600 Watts in the 8 hours I was at work (It uses about 12W an hour), or there's something else sucking a lot of battery power that the convenience consumers doesn't indicate causing alternator to work hard again. I'd think that the first option is most likely.

I literally had my lights on (LED all round) blower on setting 1 and the radio on.

[Andy Beats]

So the drive home was better than normal (congestion consistent with a good drive to work). Kept an eye on aircon usage in convenuence consumers, negligible shown amounts. Ambient was 3.5C most of the way home and a few flits into windscreen venting only saw aircon not coming on. When temp crept to 4C aircon use was up again when I briefly selected windscreen venting only (confirming the 3C cut-off for aircon).

So decent lack of congestion, negligible compulsory aircon, and still only 34.8mpg. The stop-start was unavailable again, suggesting high alternator load to charge the battery again, but battery was still a healthy 14.2v as it was at the end of my commute to work this morning.

Either the convenience consumers indicator of consumption massively overstates usage, or my dashcam gobbled up about 600 Watts in the 8 hours I was at work (It uses about 12W an hour), or there's something else sucking a lot of battery power that the convenience consumers doesn't indicate causing alternator to work hard again. I'd think that the first option is most likely.

I literally had my lights on (LED all round) blower on setting 1 and the radio on.

How are you determining the 3C cut off for aircon?
The light on mine stays on all the time, if the 'windscreen' selection is chosen on the rotarty knob.
There isn't a temperature at which the light goes off.
Minus 1.5C this morning, aircon light on.

[monkeyhanger]

So the drive home was better than normal (congestion consistent with a good drive to work). Kept an eye on aircon usage in convenuence consumers, negligible shown amounts. Ambient was 3.5C most of the way home and a few flits into windscreen venting only saw aircon not coming on. When temp crept to 4C aircon use was up again when I briefly selected windscreen venting only (confirming the 3C cut-off for aircon).

So decent lack of congestion, negligible compulsory aircon, and still only 34.8mpg. The stop-start was unavailable again, suggesting high alternator load to charge the battery again, but battery was still a healthy 14.2v as it was at the end of my commute to work this morning.

Either the convenience consumers indicator of consumption massively overstates usage, or my dashcam gobbled up about 600 Watts in the 8 hours I was at work (It uses about 12W an hour), or there's something else sucking a lot of battery power that the convenience consumers doesn't indicate causing alternator to work hard again. I'd think that the first option is most likely.

I literally had my lights on (LED all round) blower on setting 1 and the radio on.

How are you determining the 3C cut off for aircon?
The light on mine stays on all the time, if the 'windscreen' selection is chosen on the rotarty knob.
There isn't a temperature at which the light goes off.
Minus 1.5C this morning, aircon light on.

Determining it by the output attributed to aircon on the convenience consumers screen (one of the info screens accessed by the "car" button on the head unit.

At 3.5C yesterday afternoon usage was tiny, when it hit 4C halfway home, the aircon usage displayed had gone up 6-fold, from 1/25 to 8/25 of the scale of usage (the full scale equalling 1/4 gallon an hour).

[Andy Beats]

Determining it by the output attributed to aircon on the convenience consumers screen (one of the info screens accessed by the "car" button on the head unit.
At 3.5C yesterday afternoon usage was tiny, when it hit 4C halfway home, the aircon usage displayed had gone up 6-fold, from 1/25 to 8/25 of the scale of usage (the full scale equalling 1/4 gallon an hour).

I'm still really confused as to why VW would decide the dehumidifying aspect of the aircon should be denied to owners below a certain temp, when it's actually most needed!
And why make the light go on if the aircon isn't allowed to work?
I'd say 70% of the reason I see aircon as an essential item is for dehumidifying, cooling in summer is secondary.
I'm really quite annoyed that below a certain temp my car becomes a car without aircon.

[monkeyhanger]

Determining it by the output attributed to aircon on the convenience consumers screen (one of the info screens accessed by the "car" button on the head unit.
At 3.5C yesterday afternoon usage was tiny, when it hit 4C halfway home, the aircon usage displayed had gone up 6-fold, from 1/25 to 8/25 of the scale of usage (the full scale equalling 1/4 gallon an hour).

I'm still really confused as to why VW would decide the dehumidifying aspect of the aircon should be denied to owners below a certain temp, when it's actually most needed!
And why make the light go on if the aircon isn't allowed to work?
I'd say 70% of the reason I see aircon as an essential item is for dehumidifying, cooling in summer is secondary.
I'm really quite annoyed that below a certain temp my car becomes a car without aircon.

Maybe the limit is system protection - don't parts of the system freeze up ( heat exchange system) if active while trying to cool 3C air even further? 3C air is pretty dry itself, very low capacity to hold moisture.

On the other hand, why the hell did VW decide to have aircon blasting covertly when the light isn 't on, if you have windscreen venting selected?

[Andy Beats]

Maybe the limit is system protection - don't parts of the system freeze up ( heat exchange system) if active while trying to cool 3C air even further? 3C air is pretty dry itself, very low capacity to hold moisture.
On the other hand, why the hell did VW decide to have aircon blasting covertly when the light isn 't on, if you have windscreen venting selected?

If parts of the system freeze up below 3C, then it doesn't explain why other cars operate the aircon below that temp.
As I said earlier, even my Nissan Leaf used to operate the aircon below 3C.
And that had no engine heat to use as protection against the aircon system freezing.
So what's wrong with VW's design that they have to switch it off below 3C?

[Adam_013]

Driving home tonight my Aircon light was on when the dial was set to windscreen and a terrible smell filled the cabin... Changing the direction and the A/C turning off solved this issue. But the temp was 1.5c.

If I put the A/C on manually in any other position the smell came back again, indicating the A/C was certainly on?

Surely this goes against this 3c rule?

Sent from my ONEPLUS A3003 using Tapatalk

[monkeyhanger]

Maybe the limit is system protection - don't parts of the system freeze up ( heat exchange system) if active while trying to cool 3C air even further? 3C air is pretty dry itself, very low capacity to hold moisture.
On the other hand, why the hell did VW decide to have aircon blasting covertly when the light isn 't on, if you have windscreen venting selected?

If parts of the system freeze up below 3C, then it doesn't explain why other cars operate the aircon below that temp.
As I said earlier, even my Nissan Leaf used to operate the aircon below 3C.
And that had no engine heat to use as protection against the aircon system freezing.
So what's wrong with VW's design that they have to switch it off below 3C?

Took the kids to McDonald's tonight to pick up drive-through happy meals, and with an ambient 2C The hot fòod and the 2 mouth brwathers in the back were causing some misting inside. Convenience consumers showed that heavy aircon use was available to me as standard in Windscreen venting even at 2C. Could there be a humidity sensor coming into play? Heavy aircon consumption was unavailable again shortly after the mist cleared.