A/C GASSING QUESTIONS

[MIDNIGHT RIDER]

I just added a can of 134a to my A/C all by myself for the first time ever.

The clutch was clicking off and on; and, the low-side showed about 23 on the gauge.

I added what I thought was a whole can of 134a.

This put the gauge to around 37.

I couldn't get more than 37 from it; so, I assumed the can was empty; it felt empty.

When I un-screwed the can, it spewed refrigerant pretty strongly, quite a bit.

How do I know the can is empty; or, does the can reach a point where it has equal pressure with the A/C and can do no more, even though it is not empty??

What should a properly charged system show on a gauge??

This is my first solo experience at this.

Even if I don't really know what I am doing, it is sure nice to not have to harass someone else into doing this.

Thanks.

 

[NJKen]

When you charge from a can make sure it's upside down. If its not you will get a spraying can like that!
You can not verify state of charge on one guage reading. You need a high side reading, low side reading, and a R134a temperature chart to detemine proper charge. If it is 80 degrees out you will probably see a high side of 150-200 and a low side of 25-35 with the ac set to may ant idle.
Good Luck
Ken

 

[Mr_Roboto]

You have to remember that the pressure in the can will only go as low as the pressure in the system. So if you have 37 psi in the low side, you have 37 psi in the can.

You have to be careful when charging the system with the can upside down. With the can upside down, you are charging with liquid rather than gas. If you charge a system with a charge port near the compresser, and charge with liquid you can hydrolock the compressor.

However, in systems that charge away from the compressor, it will charge must faster and you will get more out of the can when charging with liquid.

Also, I try to unhook the can right before the compressor cycles off. This is the point when the low side is at its lowest pressure.

 

[NJKen]

True. I was advising on the our trucks where the low port is on the accumulator. Liquid refrigerant into the suction side of a compressor will damage reed valves or just plain destroy the compressor.
Ken