ground fault/shocking problem

[jim creed]

have a true two door with a Tecumseh compressor ae3425yaa
box was tripping gfi, no other items on circuit, eliminated cond. fan. evap fan and thermostat, also drain line heater, everything came back to compressor, without equipment ground the box would pop you pretty good, 47 volts.
changed compressor, second one in 16 months, first one locked rotor.
5 weeks after second compressor, same problem, checked resistance from common to run and start, no reading on either, turn unit on 122vac from compressor body to equipment ground

this one has me stumped, I feel like its a simple fix but cannot figure it out, do not want to risk another compressor, not good for customer or me.

[al]

Is there acid in system, corroding windings and faulting to earth. Safeties are doing what they should and unfortunately it looks like replacement compressor is needed, is the voltage to earth there all the time or just when the compressor kicks? You've eliminated defrost heaters as well?

[The Viking]

So when the compressor(s) were replaced, did you:
- Carry out an oil test to see if the oil was acidic?
- install a burnout drier, or at least a normal drier, in the system?
- Purge the pipes with OFN whilst you were brazing?
- Properly vacuum the system to at least 1 Torr and verify that it was standing for 1/2 hour without a rise in pressure after the vac pump been turned off?

[mikeref]

Adding to "Viking's" post. Did you
- tip the last compressor and measure oil volume along with possible oil discoloration.
- Change the electrics. Relay, caps.
- Monitor fridge over several cycles... Freezer as you said Drain line heater.
- Is there a CPR in line? Check back pressure after a defrost.
- Assuming it is a 2 door freezer, is the TX set to correct superheat. ( Liquid flooding after defrost.)

[Guner Edip Riza]

Addition to comments.

Fake refrigerant. Manufactured in China which contain methyl chloride.


Reaction of the fluid used in substitution of R134a, methyl chloride (CH3Cl or methyl chloride), R40, on the aluminum contained in the compressor or in the refrigeration circuit.The POE oil of the refrigerating machine used is highly saponified by reaction with the R40 and its starting materials are separated. These reactions cause the formation of acids and alcohols.