Bamboozled o er air con

[Nath90210]

Hi.

I went to get my aircon regassed the other day. I was told there was no pressure atall in the system. Upon getting home i found the ac clutch would not engage when pressing the air con to on.

I located the relay and carried out the paperclip bypass. This seemed to engage the plate.

I got myself another relay to find when installed the aircon does not activate.

The 10a fuse in the 11 slot is working fine.

Any ideas please?

[Tannaton]

Originally Posted by Nath90210

Hi.

I went to get my aircon regassed the other day. I was told there was no pressure atall in the system. Upon getting home i found the ac clutch would not engage when pressing the air con to on.

I located the relay and carried out the paperclip bypass. This seemed to engage the plate.

I got myself another relay to find when installed the aircon does not activate.

The 10a fuse in the 11 slot is working fine.

Any ideas please?

There is a pressure switch in the system which prevents the compressor operating when there is no gas in the system - the lubricant for the compressor is in the gas to running it dry will damage it.

I would start with that... and I think it's likely that the switch will be open because the gas has leaked (again). If the system has no pressure at all, it's had a leak, which won't mend itself.

[john langrick]

Hi, I would suggest rre-gassed with a gas with UV trace..

This will leak a UV dye detectable with a UV torch.

I think most places that can regas can provide this.

On mine the condenser was leaking. It is in front of the rad so quite exposed.

Hope this helps

[XJSDriver]

John is correct but sounds like a big leak as your system could not be pressurised so a decent garage with a/c trained technicians may be able to spot the leak using Nitrogen gas. Depending on where it is, if you are handy with the spanners you may be able to fit the parts yourself and then get the garage to test and re-gas if all good saving you some hefty £s.

[Father Ted]

I'd have to ask, though: Why did the garage just fill up an empty system and send it back out. Surely they'd have had a duty to find out why it was empty, rather than just take your money?

[robsterpaterson]

They're not supposed to fill leaking systems as the refrigerant is a greenhouse gas.

[Tannaton]

Originally Posted by robsterpaterson

They're not supposed to fill leaking systems as the refrigerant is a greenhouse gas.

That's true - what they usually do first is place the system under vacuum, and hold it for 20 mins or so to check for leaks before refilling. This also extracts much of the old gas and oil, and any moisture.

However contrary to what you might think a vacuum is only a 14 psi pressure difference between the system pressure and the outside world. Parts of the A/C system can be under 200-270 psi when running - twenty times the pressure.

[XJSDriver]

Tannaton is spot on as always; I can only guess that you went to a fast fit centre whose only interest is to maximise profit so as soon as they find any issue with your a/c system they will pass you on as can be a nightmare to fix.

However, in your case most likely you have a massive leak which will be easy to find using Nitrogen gas; you can pressurise the system to 200+ psi but in your case 80-100psi will likely expose the hole. My money is on your condenser which is the radiator at the font which gets all the stones hitting it and salt corrosion. I had the front bumper off mine recently and the damage to the condenser is significant (120k+ miles) - surprised mine is still leak free; give it time!

[Nath90210]

Update: the aircon system has been fully cleaned, lubed and regassed by a local engineer, with a black light revisit to check for leaks.

All working as it should. Thanks for all the know how though! Much appreciated

[Harley Dave]

That's good news.

So, no leaks anywhere??

Cheers

Dave