how do you check a compresor operation when you get 70 pounds at the high and low side on a heat pump system could this be a reversing valve or a no pump compressor how do you tell the difference

KC13

Are you sure your gauges are connected to the right access ports? Do you hear any unusual hissing sounds? If so, stop the compressor (outdoor disconnect will accomplish this), wait a few minutes to see what pressures do, then re-start & observe. Try switching the reversing valve back and forth a few times by disconnecting & re-connecting low-voltage wire (usually "O") at outdoor unit. Check compressor amps to see if they are unusually low. If pressure is only 70 PSI and compressor is not pumping, system has apparently lost some refrigerant.

acetc

I agree with KC13, a reversing valve failure will usually fail due to the solenoid coil burning out or the slide inside the valve sticking (not moving all the way into position) this will cause a loud hissing noise, i have found this to happen during the winter when it gets water between the solenoid stem and coil during defrost, then the water freezes and dents the stem and then restricks the spring action inside the stem. Only once have I seen the slide roll over and block all ports, fortunatly the internal overload protected the compressor. Bad valves in the compressor will will still show some difference in pressure , the 70lbs. pressure while running would probably indicate that you were on the suction line with both hoses (follow KC13's advice) if compressor was not running then the system
would be very low on refrigerant. If the compressor breaks a crank it will not pump at all but the residual pressure would be much higher as tho the compressor were not running, check this situation with an amp meter with gages connected, the compressor would draw amps but not pump. Good luck, Mike