Technical air con compressor clicking on and off

[callisr]

Hi all,

so, after originally asking my question in this thread:

https://www.fiatforum.com/500/483557-1-2-air-con-compressor-engaging-off-every-x-seconds.html

I thought id update on the query i made regarding my own A/C.

In a nutshell, when I turn the A/C on in my 2015 1.2, the light illuminates on the control, the compressor clutch engages and the fan comes on. AC makes a kind of whooshing sound from the vents.

After a few seconds of running, the compressor and fan turn off (more or less at the same time as each other).

The control knob light remains illuminated.

After a fair while (maybe a minute or more) the compressor clutch engages and the fan restarts.

And so it goes on.........

It was suggested in the thread linked above, that the symptoms were suggestive of low refrigerant so this morning, whilst at the garage for new tyres, i had the system evacuated and refilled.

They evacuated 45g of refrigerant and installed 400 odd g of new.......

The system still switches on and off though (without the whooshing sound from the vents) and appears to chill the air (although it isn't very warm outside to feel much difference!)

Could anyone with a similar age car and manual A/C please turn it on and with the bonnet open, observe the operation so I can compare it with my own?

Im not convinced that my system is working correctly but would like to know for certain before going down a fault finding path.....

Cheers,

Rich

 

[Most Easterly Pandas]

Perfectly normally operation. It’ll cut in and out when required, especially this time of yeah.

Has been the case on any car I’ve owned. Especially the Fiat’s though, be it a 500, Panda, Stilo, Bravo or Qubo

 

[AndyRKett]

Perfectly normal, if the refrigerant was low and it seems it was very low the “whooshing” noise is the gas passing through the expansion valve into the low pressure side which will me a much lower pressure than normal. The cycling on and off is because the pressure on the low pressure side drops too much and the car then needs to wait for the gas to equalise before turning the compressor on again so that the compressor doesn’t get damaged trying to work when there is nothing there to compress. If it ran with low gas eventually it would damage the compressor as well as just pumping gas at a steady rate through the system, without there being enough of a pressure difference to create cooling.

I’m honestly confused why you think there is a fault?

 

[chris3234]

Think of it like your fridge at home the compressor dosnt run constantly

Same with the car once the system is up to a certain pressure theres not benefit to compressing the gas any more
Plus as this time of year there's the risk of the evaporator freezing over with the cold air

 

[callisr]

Thankyou all for the replies and putting my mind at rest!
I have never paid any attention to AC in cars before......it either works or it doesn’t as far as I’ve been concerned before!
The fridge analogy makes a lot of sense!
Thankyou all again! I appreciate it!

Rich

 

[John202020]

At 10% remaining I'm surprised it still worked?
Remember leave the a.c. on ALL THE TIME especially now in winter!

 

[callisr]

I intend to. I’m even going to do battle with the cabin filter on my next days off!!
Cheers
Rich