Afternoon all, I'd like some advice re. getting my aircon working if possible, please.

I have a 2014 A6 C7 Avant Ultra with 4 zone climate feature. Bought it late last year when it was cold and the heater works perfectly (although, thinking back, I did notice that the windscreen was hard to defog). Now the UK temperatures have started heading upwards I find that the A/C doesn't cool.

It's only ~20degC out there at the moment, but dialling the AC down to 16degC gets the fans spinning like mad, but pushing air at ambient temperature.

I've checked, and it's the same at all vents, not just the drivers.

After reading this thread I fitted a Mahle replacement pressure sensor, hoping it would be a quick and cheap fix, but it's made no difference

A VCDS scan show no errors with the HVAC systems. See the attached screengrab for figures from when the engine had been running (stationary) for about 30mins with the AC dialled down to 16degC. The compressor is running, refrigerant is at ~6bar and the vents are expecting -13degC but getting +31degC. Refrigerant was at ~3bar with the system not running.

Any bright ideas, people?

Edited April 4, 20251 yr by WiteWulf

Sounds like the gas expansion valve is not opening. I don't know how to test or repair it so you may need to visit an aircon specialist.

Thanks @cliffcoggin, time to look for a local HVAC specialist, then

Do please let us know the outcome.

Will do

Aircon gas needs replaced/recycled every couple of years to work at its best. Over time the amount in the system reduces and loses its efficiency as it absorbs moisture. I’ve found The newer 1234yf gas used doesn’t supply the same chilling effect in cars as the older r134a but is used because a change in law as its a lot more environmentally friendly. 

What progress on this problem Gary?

No progress as no money this month 😂

I promise I’ll come back with an update after I get paid and get some work done!

 

FWIW, though, I posted the same query on a number of VAG owners forums, and the same diagnosis came back every time: dodgy N280 regulator valve.

It’s a cheap enough part, but the drain and re-gas means I can’t do it myself, annoyingly. 

You can jump the electrical side of the valve to see if your aircon pump clutch engages which would confirm what your suspectin.  to change the sensor without degassing is usually possible as it should screw into a valve that will stop the gas escaping