XC70: General Heater controls /air con

[apersson850]

Yes, now I realized that you misunderstood the meaning of the LED in the button. It's a pilot light. It means that the AC is enabled, thus allowed to run when the controller finds it appropriate. And as I wrote before, it's even more sophisticated than Kev0607 hints at, since these compressors are continuously variable, not just on/off. If it's just luke warm (think typical British summer...), then it will run, but not at full capacity.

When the AC is "on", it also means that each time you start the engine, it will run for a brief moment, since compressors of this kind live longer if they are frequently rotated, since that implies lubricated. This happens even in the winter. But they have capacity enough to make a big block of ice of the whole evaporator, so they never run all the time.
So even in the old manual AC systems, like in that 744 GLT 16 valve I mentioned, turning the AC on meant that the compressor ran as much as needed to feed out cool air. It was still not on all the time, or the system would freeze.

With the LED in the button off, on the other hand, the compressor is never allowed to start. Why they have this option at all I don't understand, since there's no real point with it. Maybe to pass some consumption test, as the compressor will increase fuel consumption slightly.

[FreshAir]

Originally Posted by apersson850

Of course it can. And it does too.

That is interesting that it does that, I never knew.

I generally manually cycle it, more so the passenger who does really not understand thermostats and that having the A/C on will simply not turn the car into a fridge. Especially that the system will run much cooler on those tropical days to get the temperature down and then reduce the cooling level to maintain the temperature. A training course needed for SWMBO would be useful, same problem exists at home :-(

[apersson850]

Originally Posted by FreshAir

I generally manually cycle it, more so the passenger who does really not understand thermostats and that having the A/C on will simply not turn the car into a fridge. Especially that the system will run much cooler on those tropical days to get the temperature down and then reduce the cooling level to maintain the temperature.

With the climate control in the car, there's no point in setting a different temperature than the one you desire, in an attempt to quicker cool down/warm up the cabin. The system will work to get the temperature to the desired one as quick as it can anyway.
So the time to go from 40°C on a warm summer day to 22°C, or whatever you like, will not shorten just because you select LO to begin with, then change to 22° when you start feeling cold.

What you need to do is to set it to AUTO, of course, to allow it to use the means it has.

[FreshAir]

Originally Posted by apersson850

With the climate control in the car, there's no point in setting a different temperature than the one you desire, in an attempt to quicker cool down/warm up the cabin. The system will work to get the temperature to the desired one as quick as it can anyway.
So the time to go from 40°C on a warm summer day to 22°C, or whatever you like, will not shorten just because you select LO to begin with, then change to 22° when you start feeling cold.

What you need to do is to set it to AUTO, of course, to allow it to use the means it has.

I know that.... but someone at home does not grasp this simple control system functionaility. I must have the only passenger that turns off the AC when its 24 or 25 deg C outside. Then 5 minutes later decides its too hot and turns it on again and then complains about the icy draft as the system has so much cooling to do. Should just leave at required temperature and let the clever control system do it for you.

[apersson850]

I see.

In general, Americans seem completely baffled by automatic climate control systems. They tend to set the fan speed very low manually, select air outlet to the windscreen and floor and then set the temperature selector to LO, trying to mimic how their air conditioning systems worked when they were introduced, many decades ago.

Instead of letting the systems the car manufacturers have spent a lot of resources in developing do their job.

[yostumpy]

Now then, had to go out tonight, and although not cold, was a bit damp and chilly, and I was cold before I left the house. So.....set temp at 21.5 deg, opened all the dash vents and pointed skywards, hit auto and a/c came on. Drove a sort distance and it started to warm up quickly, but I was still cold....ah! I know, what about these seat heaters then. So popped it on 2 and within a few minutes I was toasty warm, so I had to turn seat down to 1, then eventually off, and even turned main temp down. It’s quite amazing that the seat heaters actually warm your body, not the air, so you feel warm right through, even though the air is not.. also they seem to stay very warm long after the thing is switched off. It’s definitely the warmest I ve been in it. Thanks for all the advice.

[apersson850]

I have the seat heater in the driver's seat set to turn on automatically when it's cold outside. Same with the mirror/rear window demist.

The seat heater always starts at full throttle (three out of three). After two km of driving, I reduce the power level to one of three, which I then let it stay at for the duration, at this time of the year. It's still thermostat controlled, but it doesn't need to fire up so drastically each time the seat gets cool enough to turn it back on again.