question about recharging a/c

[ejaymclane]

The air con didnt work on my 'new' car. I checked the pressure with a gauge and it read zero. I bought a can of EZ Chill and began refilling my car. Ive used the stuff before on a previous car and normally the pressure builds gradually as you add the freon until there is enough to make the compressor come to life.

Well, this time the pressure went from zero to reading 'charged' within ten seconds. The compressor hadnt come on so i knew it wasnt and it didnt make sense anyway. I waited and then started adding more freon and the compressor switched on and started cycling on and off until id added enough gas to make it work continuously.

The a/c works but why did the pressure rise from zero to showing a full charge within seconds?

Even as i added more gas the pressure didnt really change. I emptied a whole can of freon in and the pressure remained within the middle of the 'charged' part of the gauge.

Any help?

[JayP71]

Defective gauge? If you were using one of the cheap ones mounted to the $19.99 can o' R134a anyway. I've seen these not work right before.

[Darwin686]

Did the compressor cluck click right before the guage activated? If so you have a pressure shutoff valve built into the compressor designed to keep compression in the system. When the compressor engages the valve is opened and pressure is released back into the entire system. If not then you have a faulty guage