Climatronic - what does the A/C button do?

[reserves]

I know this sounds like a silly question but I’m trying to diagnose a heating issue.

The manual says switch A/C on to cool the vehicle.

However surely the temperature selector sets the temperature?

If I set it to ‘Auto’ & 22 degrees surely this is what climatronic does in terms of it keeps the temp at 22 degrees knowing if it need to heat the car up or cool it down.

So, can someone help me understand what the A/C button does in this case.

For example the cabin is at 19 degrees and the temperature is set at 22 degrees surely it shouldn’t be possible to activate the A/C at all as the vehicle needs heating rather than cooling. So why is an A/C button even needed?

2017 T6 Ocean

 

[JollyGoodShow]

The AC button de-selects the AC compressor, saving fuel. The AC compressor cools the air, allowing you to have the car cooler than the outside air temperature. It also dehumidifies the air, reducing condensation. In winter you can warm the car without AC but you will get more fog on the interior glass, which you can disperse by opening a window. In summer you can’t cool the van without AC if it is hot outside.

The button gives you the choice to save fuel by not using the AC. I would leave it on all the time unless you are hypermiling.

 

[dspuk]

Heating and cooling of a car depends on three things. Outside temp. Engine temp. Air con.

If it’s 25 degrees outside and you set the temp to be 18 no amount of air coming from outside will get you down to 18. Try driving a non aircon car in Spain.

So the a/c gives you that cooling by passing the air over a condensor.

You can leave it on more of less all the time. When the temperature setting does not need it, say setting it to 20 in winter, it wont use it, just the engine temp to heat up the air.

 

[chockswahay]

I have a 6.1 so a bit different but I believe it is simply a case of regardless of heat demanded you either condition the air or not. Perhaps the biggest difference is that with air con selected you can cool the interior of the van below ambient temperature whereas heat only (no air con) can only raise or maintain a temperature equal to or higher than ambient……..

If any of that makes any sense

 

[chockswahay]

Haha, the previous answers are more accurate and succinct than my poor attempt

 

[chockswahay]

My son leaves his 2017 T6 aircon on all the time (I’m too mean)

 

[Ch1pbutty]

Have always left ours switched on. Only switched off ifwe have the windows wound down with engine running.

Most issues with aircon seem occur when left switched off for long periods, then the cost to fix will far outweigh any fuel saving.

 

[Roger Boeken]

You can activate central heating at home in middle of summer , it will be active but not heating if room temperature is higher than demanded.
I believe in cali air with A/C turned on is always cooled and then heated to get temperature selected. The big advantage is that the cooled air is dried because water vapor will condensate before it enters the cabin and the dry air will make it easier for example to clear the windshield of fog. I must check the manual but i think below 5 deg C A/C will not work.
A reason to switch it off if not needed is fuel consumption and lifetime of parts involved.

 

[WelshGas]

AC does 2 things when On.
1. Cools the air to about 10-12c.
2. Cold air carries less water, humidity, so the air coming out of the AirCon heat exchanger is both cold and dry.
The next stage is the standard, non AirCon heat exchanger which raises the temperature to the set level giving Warm Dry air with a lower humidity than the outside air.

In winter using AirCon on re-circulation will take internal rather than external air and adjust its temperature but also dehumidifies the air so helping the interior keep dry .

Mine hasn’t been Off for the last 9 yrs/125,000 miles,

 

[reserves]

Thanks all.

I’m still a bit confused.

If the temp inside is 18 degrees and the heating controls are set to 23 and ‘Auto’ and ‘A/C’ is switched on the what is the air con compressor doing in this instance? Is it simply switched off as it’s only designed to pass cool air?

If so is the A/C button simply doing nothing in this instance?

Feel like I’m misunderstanding something basic here.

 

[dspuk]

Depends on the outside temp. If less that 5 degrees it switches off anyway, even if your button is on.

In your example though. 10 degrees outside. Set to be 18 in.

Aircon on - the air being pulled from will be cooled over the condenser and then heated back up again to 18 by engine heat as per your setting. This also removes water from the air so reduces condensation inside. Why aircon air is so dry.

Aircon off. The air being pulled from outside bypasses the condenser (or it is “off”) and only heated to 18 by the engine. Water will contain condensation if it’s particularly humid outside.

Are you trying to understand how it works or work out if you should leave off to save money? What is your heating issue?

 

[reserves]

Depends on the outside temp. If less that 5 degrees it switches off anyway, even if your button is on.

In your example though. 10 degrees outside. Set to be 18 in.

Aircon on - the air being pulled from will be cooled over the condenser and then heated back up again to 18 by engine heat as per your setting. This also removes water from the air so reduces condensation inside. Why aircon air is so dry.

Aircon off. The air being pulled from outside bypasses the condenser (or it is “off”) and only heated to 18 by the engine. Water will contain condensation if it’s particularly humid outside.

Are you trying to understand how it works or work out if you should leave off to save money? What is your heating issue?

Thanks for your reply.

I’m trying to figure out if I have a heating problem, which i think I do.

Was wondering if I had my expectations set incorrectly.

If I set the temp to 23 at the moment (given it’s way colder than 23 when I start the Cali) it blows hot air as long as I keep the ‘Auto’ function off. When I switch ‘Auto’ on the fans hardly blow and it’s like the Cali already thinks it’s at a warm enough temperature.

When I turn Auto on it also turns the A/C light on so I was wondering if that is causing an issue or what the expected behaviour is.

I’ve hooked the Cali up to VCDS and monitored the readings of the inside cabin temp, air vent temps etc. they all seem fine but I’m not 100% sure what I’m looking for.

Seems like a temp sensor is faulty somewhere but can’t figure which one as they read fine.

So guess I was just trying to eliminate the A/C function at this point.

Any ideas I’d be super keen to hear!

 

[dspuk]

Thanks for your reply.

I’m trying to figure out if I have a heating problem, which i think I do.

Was wondering if I had my expectations set incorrectly.

If I set the temp to 23 at the moment (given it’s way colder than 23 when I start the Cali) it blows hot air as long as I keep the ‘Auto’ function off. When I switch ‘Auto’ on the fans hardly blow and it’s like the Cali already thinks it’s at a warm enough temperature.

When I turn Auto on it also turns the A/C light on so I was wondering if that is causing an issue or what the expected behaviour is.

I’ve hooked the Cali up to VCDS and monitored the readings of the inside cabin temp, air vent temps etc. they all seem fine but I’m not 100% sure what I’m looking for.

Seems like a temp sensor is faulty somewhere but can’t figure which one as they read fine.

So guess I was just trying to eliminate the A/C function at this point.

Any ideas I’d be super keen to hear!

When you set to auto it won’t blow till the engine is hot enough. When you don’t it will do as you set the switches.

Auto switches on AC by default.

TBH. Doesn’t sound like there is anything wrong.

 

[WelshGas]

Thanks for your reply.

I’m trying to figure out if I have a heating problem, which i think I do.

Was wondering if I had my expectations set incorrectly.

If I set the temp to 23 at the moment (given it’s way colder than 23 when I start the Cali) it blows hot air as long as I keep the ‘Auto’ function off. When I switch ‘Auto’ on the fans hardly blow and it’s like the Cali already thinks it’s at a warm enough temperature.

When I turn Auto on it also turns the A/C light on so I was wondering if that is causing an issue or what the expected behaviour is.

I’ve hooked the Cali up to VCDS and monitored the readings of the inside cabin temp, air vent temps etc. they all seem fine but I’m not 100% sure what I’m looking for.

Seems like a temp sensor is faulty somewhere but can’t figure which one as they read fine.

So guess I was just trying to eliminate the A/C function at this point.

Any ideas I’d be super keen to hear!

Is the vehicle upto temperature when this happens?
If not then the possible scenario is that there is enough engine heat to raise the temperature of ambient air ( AirCon OFF ) to above 18c so the fans blow to get the temperature to your setting of 23c.

However, if AirCon is ON, there may be insufficient engine heat to raise the temperature above 18c ( remember the incoming air has been cooled compared to ambient air temperature by the AirCon heat exchanger ) so the fans won’t push the air through until it has been heated to 18c +. Once the incoming air is heated above 18c then the fans will speed up.

 

[B J G]

Air Con compressor is only used to cool air so not operating in winter in theory but in practice on a long run the cabin will warm gradually and if a sunny day there will be some solar heat resulting in the inside temp going over the preset temp when this will cause the compressor to cut in cooling the inside.
Your fingers/hands are usually the first part to sense this cooling action.

 

[DavidofHook]

I keep my aircon on all the time as this helps to stop the piping from drying out. This can result in a very expensive replacement as I found out with a Ford some long time past! Keeping it on requires more energy but I have not found that has made much if any difference to my MPG. And any loss here is offset by not having an expensive aircon replacement job on your hands!

 

[reserves]

Update: I removed my head unit and pushed all the plugs in the back of the A/C unit to check they were all plugged in correctly

I’m not sure if this fixed anything or my understanding has changed.

For now I think my Cali is acting as do.

Just surprised that the fans don’t blow more when the air is hot, the inside temp is 18 and I want it to be 22