A/C prob. - Seeking hint

[Claude]

Here are the facts:
1) no cooling air at all (the problem) whatever is the A/C temp setting.
2) system have been converted to R-134 2 years ago at that time condensor and receiver/dryer have been also change as well as the the compressor oil.
3) compressor cluch operate well when A/C button is activate and compressor seems to run fine (no special noise / no apparent oil leak)
4) the slow speed resistor on the électric fan un front of the condensor have been bypass so when A/C is activated this fan also run max speed

Any clue / hint / what to check

[Tiger]

Sounds like low refrigerant level. Check pressure... it needs to be around 27 to 30 PSI when the compressor is running. I think it needs 50PSI static to trigger compressor to run.

[Claude]

Sounds like low refrigerant level. Check pressure... it needs to be around 27 to 30 PSI when the compressor is running. I think it needs 50PSI static to trigger compressor to run.

But the compressor run right away after i push the A/C On/Off button so the pressure should be OK ! But instead of cycling like before the compressor now runs continuously without giving any cool air. I always thought that without the minimum refrigerant level the system inside pressure will be too low and a pressure switch will prevent the compressor clutch to operate so to protect the compressor itself.

[Scott C]

But the compressor run right away after i push the A/C On/Off button so the pressure should be OK ! But instead of cycling like before the compressor now runs continuously without giving any cool air. I always thought that without the minimum refrigerant level the system inside pressure will be too low and a pressure switch will prevent the compressor clutch to operate so to protect the compressor itself.

Can you pop some gauges on there to see what is going on? Would help a lot.

Scott

[bmwrp8]

Sounds like low refrigerant level. Check pressure... it needs to be around 27 to 30 PSI when the compressor is running. I think it needs 50PSI static to trigger compressor to run.

+1 if your refrigerant is low but not low enough to not let the compressor work you'll still have insufficient cooling. Put a gauge on it. It can also mean your compressor is not pumping right that you might need to replace it even if visual check is ok and no funny sound can be heard.

[Tiger]

We need pressure reading.

[Ross]

Probably low refrigerant but heater valves stuck open would warm the chilled air.