Air Con: Aircon pump cycling

[glengibson]

Hi all,

Recently had a new condenser fitted due to refrigerant leak. Now it’s actually sunny today, turned aircon on and doesn’t seem to be getting very cold. I’m presuming it’s not a refrigerant level issue as it was only gassed with the new condenser a couple of weeks ago.
What I have noticed it the compressor is cycling. On for approx 5 - 6 seconds then off for about 12- 15 seconds.

So my thinking is: either compressor/clutch or thermal expansion valve??

Any input on this would be great thanks 🙏🏻

[Tannaton]

The "duty cycle" of the compressor is controlled by the temperature of the evaporator (which is the heat exchanger behind the dash which does the cooling). The compressor will be engaged and disengaged to keep the evaporator cool enough to achieve the desired cabin temperature but not so cold it is likely to ice up (ice crystals form and block the airflow).

On a mild (rather than hot) day with only minimal cooling required - short cycling would be quite normal.

But if the system is low on gas (i.e. a leak in the new condenser or one of the joints that was disturbed) that can cause short cycling too.

If you have VIDA I think you can read off the temperatures and pressure switch status.

[glengibson]

Thanks for the response. I do have Vida, will have to have a look and see if I can find it.

[reggit]

Have you measured the clutch gap on the air in compressor?

They wear and get too wide, it’ll usually start working then cut out after a few minutes. Cheshire D5 has a video on YouTube explaining a repair without taking the compressor out - did this on my old P2 and it restored functionality.

[glengibson]

Yes I’ve seen the video but it comes on straight away, works for about 6 seconds then goes for for about10 then on for 6??

[Kev0607]

Originally Posted by glengibson

Hi all,

Recently had a new condenser fitted due to refrigerant leak. Now it’s actually sunny today, turned aircon on and doesn’t seem to be getting very cold. I’m presuming it’s not a refrigerant level issue as it was only gassed with the new condenser a couple of weeks ago.
What I have noticed it the compressor is cycling. On for approx 5 - 6 seconds then off for about 12- 15 seconds.

So my thinking is: either compressor/clutch or thermal expansion valve??

Any input on this would be great thanks 🙏🏻

Was the refrigerant definitely re-gassed? You'd presume they would have added refrigerant, but maybe they didn't add enough or maybe put too much in!

They should have pressure tested the system after fitting the new condenser to check for leaks. Maybe you still have a refrigerant leak?

I'd bring the car back to them & tell them the air con isn't working properly, despite getting a new condenser fitted.

Its possible that they didn't add the correct amount of refrigerant, or you still have a leak.

[oragex]

Also, what is the outside temperature at your place ?

[Tannaton]

Originally Posted by oragex

Also, what is the outside temperature at your place ?

At the moment typically 4 - 8 degrees C during the day. The metropolis of Kingston Upon Hull is a North Sea port so typically 2 - 4 degrees cooler than the mainland UK. Last weekend there was the most unusual phenomenon of nice weather - 13 degrees at the end of February. Also known as “summer”.

[Tannaton]

Originally Posted by Kev0607

Was the refrigerant definitely re-gassed? You'd presume they would have added refrigerant, but maybe they didn't add enough or maybe put too much in!

They should have pressure tested the system after fitting the new condenser to check for leaks. Maybe you still have a refrigerant leak?

I'd bring the car back to them & tell them the air con isn't working properly, despite getting a new condenser fitted.

Its possible that they didn't add the correct amount of refrigerant, or you still have a leak.

I think that’s the way to go - a quick test of the pressures on the high and low side will tell if the system has enough gas in it and is healthy.