I deal mostly in residental hvac but take care of a store close to my house. I'm having trouble with a Howard McCray GF75LBM reach in freezer. It uses 404a refridgerant . I moved the condensing unit two years ago from inside the cabinet to the other side of the wall betwwen the walk-in and outter store wall around 2 years ago . The system has ran just fine and still runs great as far as keeping the temp inside the freezer where it should be. Recently the customer told me he was hearing a loud vibrating noise coming from the unit after defrost. What I found is the noise is coming from the crank case pressure regulater. My head pressure gauge vibrates so fast you can't hardly see it until the suction pressure goes down to aroun 35 or so psig , then the noise stops and all is well . I know the CPR is working because the suction climbs only up to around 48 psig while the systen is in defrost. The CPR does not vibrate during a regular cycle , only in defrost . This system does not have a soleniod . My super heat and subcool is very high SUCTION PRESSURE 20 PSIG ---LINE TEMP 69.5 ---- HEAD 315---- LINE TEMP 184
I am going to clean the condensor coil tommorow and already have the new CPR valve ready to put it on . I just want to be sure when its on and cleaned we don't have the same problem.
The unit seems to run really well other than the problems I mentioned , ant suggestions would be greatly appreciated