I have some a/c exp, recent purchased older home that has 4 HP's. one OK, one has stuck compressor,5ton, but whats stuping me is the other 2Ton Carrier units? both I vacumn to 25+ in", started charge, they go to over 200psi in suction side, rev valve ok, can someone explain? problem,

thanks
ric

hvac1000

If it is going to 200 on suction side the reversing valve has to be defective. It is the only link the suction side in A/C mode has with the high pressure side. Valve could be stuck/bad coil or bad internal valve allowing leakage of high pressure to low pressure area.

Are you sure it is going into the A/C mode? 200 psi is a reading you would get if running as a heat pump.

BTW it could also be your metering device or lack there of allowing a flooded evaporator which would in turn cause a high suction pressure. Caution do not run in that condition for long periods of time. Compressor failure can and will happen.

You can recover the refrigerant and try some Supco 66 lube to see if it will break free if the valves internal parts is at fault. Also you can gently tap the reversing valve to see if it will help unstick it.

Do all other electrical checks before you service the sealed system.

JackT

Where did you hook your low pressure hose? If you connected it to the suction line at the valve where it hooks to the unit, I'll bet your in the heating mode. When you run the unit does the suction line get hot? On heat pumps there's usually a second valve that you can hook your low side hose to above the two copper lines. This valve is connected directly to the compressor suction line.