Aircon over pressure

[jonbarrett]

Aircon on the A-Class failed and before calling out the experts I decided to try the Halfords DIY aircon kit. Attached the gauge and it said the system was low. Pumped in some new gas and like magic it was back to normal. Following that success I decided to try the Cerbera which als so has poor aircon. This time the gauge said the system was over pressure, way over into the red danger zone!

Would too much pressure cause the system to not work properly? If so can I simply bleed some our or will I die in a cloud of poisonous aircon gas?

[mikesr]

Yes too high or too low pressure turns off the aircon via the switch fitted to the receiver drier bottle in the front wing

I believe it is illegal to vent the refrigerant into the atmosphere.

[Ireland]

mikesr said:

Yes too high or too low pressure turns off the aircon via the switch fitted to the receiver drier bottle in the front wing

I believe it is illegal to vent the refrigerant into the atmosphere.

All true.

You're probably best to have the system vacuumed and recharged with 650g of R134a.

And then accept the fact that your cars air-con will never be as good as that in a sensible car.


BTW speeding is illegal too.

[jonbarrett]

Strangely, when it does work I get a real blast of ice cold air but only for about the first 5 iles, then nothing.

[ridds]

Pretty sure that's too much gas. The pump runs pretty much all the time on these unlike cars that cycle the pumps in and out.

This raises the temp of the fluid I believe and then causes the pressure in the system to rise. This then causes the Trinary switch to trip shutting the system down.

You could try turning the A/C off for a while and then on again. Or get the system vac'd and put a little less gas in.

[jonbarrett]

I had the system cleaned last year. Is there anyway I can drop the pressure a little my self (safely and legally) just to see?

[ridds]

Errr, no niether.

Only way is to pop the high pressure fill plug out and "vent" some off. Not really dangerous but not not legal as all Refrigerant should be captured really.

[FUBAR]

Kwik Tit refilled mine recently with 850g and its now blowing colder than a penquin's fart

[jonbarrett]

That's interesting because Ireland is recommending 650g. I've seen this debated before, any definitive answers?

[ridds]

I'd go for 750g.

[optimax sniffer]

I had 850 put into mine, but was told afterwards that it should be 950

[Byker28i]

My guy called the factory just after I got the car and they told him 600g and Pag46 oil.

[Byker28i]

Jum - just looked up that product - looks interesting
http://www.halfords.com/webapp/wcs/stores/servlet/...

Air Con Measure & Charge Refrigerant & Oil with Leak Sealer, helps seal leaks in rubber hoses, gaskets and O rings.

Features and Benefits:-

* Restores refrigerant and oil
* Seals leaks in hoses,gaskets and O rings
* Cleans system deposits
* Improves efficiency
* Reusable hose with gauge
* 19oz can

All for £40.

[FUBAR]

Byker28i said:

Jum - just looked up that product - looks interesting
http://www.halfords.com/webapp/wcs/stores/servlet/...

Air Con Measure & Charge Refrigerant & Oil with Leak Sealer, helps seal leaks in rubber hoses, gaskets and O rings.

Features and Benefits:-

* Restores refrigerant and oil
* Seals leaks in hoses,gaskets and O rings
* Cleans system deposits
* Improves efficiency
* Reusable hose with gauge
* 19oz can

All for £40.

Im guessing that system just tops up the refrigerant?

Kwik Tit suck all the old stuff out, test the system and puts fresh stuff in for £37 (with the 10% voucher)