V50 AC : Air-con fault V50, 2007

[mogle]

V50, T5, AWD, 2007

I got problems with the air-con. The car has been to my Volvo garage twice and once to Quick-Fit due to this fault. The fault is still there.

This is intermediate. Normally the Air-Con is working normally. I always keep it on auto. Then the fault kicks in. It takes about 30 seconds, you can feel the air-con is blowing moist into the car. The front window get fogged within 30-60 seconds. I then turn the air-con off, and set the blower on full trust. It can take 5 minutes for the window to clear. The air-con need to rest for 5-15 minutes. If I turn it on too early, it will fog up the front window.
The car is dry inside, there are no dogs or other ting in the car that could generate lots of air moist.

I turn the air-con on after 10-15 minutes. It then works fine, until it again kicks in with a blast of moist to the front window.

This is a huge security risk or hazard. The front window is completely fogged up with a few seconds, where it is impossible to see anything.

My Volvo service centre checked the air-fluid, and replaced it. They also replaced an internal thermostat. Cleaned up any possible debris in the air-con intake and out take. We have had this fault for more than a year now.

Any advice?

[Welton]

I don't use the air con in the winter, all it does is introduce moisture into the cabin. I fully understand how air con works it's part of my job but basically when you use the air con in winter you will get a lot of water droplets collecting inside the climate control 'box' behind the dash. This box contains the evaporator (covered in water droplets) and the heater matrix.

When you use the car all this excess moisture steams up the windscreen until you switch on the a/c and the whole cycle repeats.

The incoming air is 'dry' in winter anyway so does a good job of demisting without the need for a/c so you're better off having a completely dry climate control box and clean glass inside. I have no issues with steamed up windows.

If your air con is running normally you can sometimes get this steaming up as the a/c compressor runs on/off itself based upon the system pressure and at this time of year the time between 'off' cycles is greatly extended....leading to steamed up glass.

[mogle]

Interesting comments.

I am Norwegian and used to drive in snow and cold conditions before I move to UK. Back home the advice is to keep the air-con on even on the winter. It will help in the morning when you clear the car from ice and possible snow.

I am sceptical to your advice, but will give it a go.

#

Can you then explain:

When it is around 10 degrees outside, and wet, the air-con got this fault over and over again. Turn it off permanent, is not solving the problem.

When over 25 degrees, the just generates moist of the front windows on a random basis.

A few years back I kept the Air-Con on all the time when using the Volvo. The car and windows was fine. This just started the last year.

[Welton]

I don't really understand what the problem is from your description, it almost sounds as if the evaporator is freezing up which would be a problem with the evaporator temperature sensor, or the system has been over-gassed. It there ice forming on the bigger of the two pipes in the engine bay?

Re: steaming up - have you ever turned off your air con in cold weather and the windscreen steams up quite quickly? this is the moisture in the climate control box I spoke about. If you hadn't been using a/c then the moisture would not be there.

[mogle]

Originally Posted by Welton

I don't really understand what the problem is from your description, it almost sounds as if the evaporator is freezing up which would be a problem with the evaporator temperature sensor, or the system has been over-gassed. It there ice forming on the bigger of the two pipes in the engine bay?

Re: steaming up - have you ever turned off your air con in cold weather and the windscreen steams up quite quickly? this is the moisture in the climate control box I spoke about. If you hadn't been using a/c then the moisture would not be there.

Thanks, I will check and look for ice after the car has been running for some time.

And yes. I have started the car with the air con off in cold weather where the windscreens quickly steams up. That has been the problem, I am sitting in the car at work in the evening, waiting for the windscreen to clear. When I start the engine, the windscreen is clear, then within short time it steams up.

[Bungo]

Sounds like pollen filter.
You are right, air con will come on when you select windscreen demist, so should not be doing the opposite.