Refrigeration unit issue advice appreciated
Hello all, first post here as I usually work on engine driven AC systems. Recently we started installing Reefer units for vans and box trucks with engine driven compressors. However we installed a 230 volt single phase system on a mobile morgue trailer for the fire department. I did not complete the install, but I’m told it cooled great when it left in November of 21. It came back and I am having trouble getting the unit to cool and even the MFG is having a hard time helping me diag the issue. The compressor is a Copeland scroll single phase with an externally equalized valve. The unit also has a CPR valve set to 35 psi. 404a refrigerant. First run pressures 35 suction 275 discharge at 100 degrees ambient. However the evaporator warm nothing sweating. MFG support said likely exp valve. Tried adjusting no change. Also, clamped off the hot gas line (made of rubber) no change. They sent replacement installed, same results. CPR valve replaced under similar circumstances. They then sent me a new evaporator unit which I installed today which didn’t change anything. I suspected the evaporator is being flooded, but I had no port between the evap outlet and the CPR. Today I installed a port to check the actual suction pressure leaving the evap and it was 210 psi. Discharge 265 psi. I called for support and the person I’m dealing with couldn’t tell me if that is normal. Says they never look at that pressure. It seems way to high to me and would explain why nothing is getting cold. It’s almost like the expansion valve is not there. Playing with the valve adjustment I got it down to 150 psi but still don’t cool, distributer tubes not cold nothing. If I dip the sensing bulb in ice water the suction comes down to 85 psi and it tries to cool, but the evaporator outlet never gets cold. The hot gas line was pinched off during the entire runout. I’m starting to wonder if the evaporator distributor could be wrong, or missing the nozzle. Expansion valve too big, or maybe something with the compressor. I’m just at a loss as I’m not experienced with this style of unit. I don’t like throwing parts at anything, and this thing has been at our shop for months now. Any ideas, advice or tests you all my have would be very helpful.