I am having A/C issues. I have replaced the A/C clutch and the High pressure switch then tried to fill with R134A and we could not get the low pressure above 30. The compressor would cycle off and on but the A/C clutch would not stay engaged. I want to replace the low pressure switch but I am not sure what the part number is. I need to pick one up at AutoZone so that part number would be helpful. I am trying to eliminate all problems before I take it to an A/C shop. I have all the gauges and equipment to fill the system just cant seem to get it working properly. Any extra advice would be helpful. Thanks and have a good day.

 

You did evacuate the system to as close to 30 inches of vacuum as you could get it before adding refrigerant, right? If the compressor is cycling, the switch is at least working. It sounds like you didn't get enough refrigerant in it and it's still undercharged. How much refrigerant did you get in it (in ounces)? What are the low and high side pressures when the compressor cuts off and when it kicks back on?

 

What was the High-Side Pressure?

 

High side pressure was at 110 and the low side was getting to 30 and then when the clutch engaged it would drop to 25 or so. I never could get the low side to get above 30 and there was still plenty of 134 in the can.

 

No disrespect intended, but you should really take it to an A/C shop and have them evacuate and recharge the system. MVAC systems aren't nearly as simple as the "A/C Pro" commercials on TV try to lead people to believe they are. Moisture and air in a refrigeration system can destroy it from the inside out, and cost you far more than it would have to just get it done right in the first place.

 

Doesn't appear that you're getting R34a into the system.

1. Did you evacuate the system?

2. You can jump the low pressure safety switch with a wire to activate it to allow refrigerant to flow into the system. Also, heat a pot of water to 125*F and place the refrigerant bottle in that while charging the system.

 

I am not using A/C pro but you are right. I will just get it by the local A/C shop and get it looked at.