More on the saga of my ZR61 single phase R22 compressor problems with my geothermal system. In summary the compressor is drawing about 10 amps more than the table (curve) shows at every operating point on the curve.
Here is what we have done to trouble shoot the problem:
1) Replace Start and Run Capacitors
2) Replaces Start Relay
3) Replaced starter contactor
4) Replaced in line filter dryer
5) Made multiple measurements of the motor current with 3 different clamp on meters…all read about the same high current
6) Made multiple measurements of the suction and discharge pressure with 3 different gauge sets…all read the same suction and discharge pressures
7) Removed the compressor and installed a spare ZR61. Put brand new oil in it.
8) The spare compressor (only slightly used) had the same running characteristics as the unit it replaced. About 10 amp more current than the table for any suction/discharge pressure combination
9) We ran it in the Cooling mode (55 psi suction 170 psi discharge) measured about 25 amps…chart says we should measure about 16 amps) but the compressor has the best sound in this mode…sort of hummed …no rattle
10) Ran in the hot air heating mode (65 psi suction 220 psi discharge) measured 29-30 amps chart says should be about 19-20 amps*
11) Ran in hot water mode (like hot air but water heat exchanger instead of air heat exchanger) (65 psi suction and 320 discharge) measured 37 amps chart says about 27 amps.*
12) Pretty much nothing left to replace Our old notes show that when this unit was initially started with the first replacement compressor (we have replaced 6 so far) at 65 psi suction and 250 psi discharge we measured 23.9 amps which is close to your chart (22 +/-). So in theory the proper current was measured at one time
• * compressor runs with a slight rattle sound at these higher pressures.
In summary we are at our wits end. Assuming compressor table is accurate, and compressor/pump theory holds, then knowing the suction and discharge pressure should establish the point on the pump/compressor curve. The only items that might be impacting this and these are wild guesses at this point are the following:
1) There is too much oil entrained in the R22 causing ???
2) The mass flow rate through the compressor is much higher than we figure thus causing the compressor to draw more current?
3) The compressor is connected to a Crankcase Regulating Valve (CPR, which is tied to an accumulator). The CPR valve regulates the compressor suction pressure to keep it under 75 psi, maybe the flow is restricted somehow?
4) Maybe some sort of flood back...guess we can add a site glass??
None of this makes any sense at this point unless we are missing something????