Air con pressure

[anucatone]

Hi guys,

Have this morning regassed my air con with a Halfords kit because it wasn't working. When I first attached the pressure guage it was on zero.

However I'm a little confused about the pressure readings. When the compressor is on it's around 25psi, which is adequate but not great - should be about 40. But when the compressor switches off it leaps to 50psi, which according to my guage is in the red. Which is the reading I should be paying attention to? Compressor on or off?

It's working now, blowing cold air, but I've held of putting any more refrigerant in until I know that upper reading is not one to worry about.

Any thoughts?

[Poohbear]

I wouldn't touch a Halfrauds kit with a bargepole. The amount of refrigerant is critical to the operation of the system and unless you have all the right equipment you can't possibly get it right. Far better to pay a professional to do it.

[Coradia63]

Hi,

Normal approx pressures in a a/c systems are 20-35psi on the low side and 150-200psi on the high side with the compressor running this will vary depending on ambient temperatures the hotter it is the higher the pressures when the system isnt running the system will equalise so the pressure will rise in the low side higher than the normal running pressure.

I agree with poohbear you have to be careful topping systems up to much refridgerant will damage the system also if the system was at zero pressure there is a good chance there is a leak so the top up may not last very long alot of garages refill systems for under £50 and they have to leak check as it is illegal to refill a system with a know leak.

Hope this helps

Cheers
Stuart

[Simon Jones]

There is a handy fact sheet: http://www.igmaynard.co.uk/bongo/member ... aircon.pdf

If the pressure was at zero, then it sounds like you have a serious leak, so I would definitely recommend taking it for a professional test otherwise you'll just be wasting your money as the new gas will soon vanish. Had mine drained, tested and regassed for under £50.

[anucatone]

Thanks.

The low and high pressures match what you describe as normal, Stuart. I'll see how long it lasts.

Air cOn didn't work when I bought it but now apparent the low pressure switch had deactivated the compressor. May not be a major leak but slow dwindle over the years.

Would I expect to see physical evidence of a leak in terms of liquid on the ground?

[teenmal]

Thanks.

The low and high pressures match what you describe as normal, Stuart. I'll see how long it lasts.

Air cOn didn't work when I bought it but now apparent the low pressure switch had deactivated the compressor. May not be a major leak but slow dwindle over the years.

Would I expect to see physical evidence of a leak in terms of liquid on the ground?

Hi,
Most of these refill kits have a sealant incorporated,you need to give it a bit of time to work,the last one that I did,I had to top it up after about 4 weeks.It is still working fine 2 years down the line.

Cheers.