Chosen Solution
I have a recurring problem with a GE Profile PSB48LSRABV. Here’s an example sequence: Fresh food compartment set to 37F on the control panel (for months)Thermometer in fridge reads 46F (with lots of water inside per manual)Press “Display Temp” button, display shows fridge at 37FTurn power off, count to 15, turn power on, wait for control panel to bootPress “Display Temp” button, display shows fridge at 46F (matches thermometer!)Compressor runs and cools fresh food compartmentHours later thermometer in fridge reads 37-38 (yeah!)Press “Display Temp” button shows fridge at 37FWithin days, the fridge is warmer inside again, thermometer inside reads 45+, but display reads 37 - unit needs to be “rebooted” again! Fresh food thermistor from top of cabinet measured properly in ice water (and warmer water), the unit has always passed all the self-tests, and condensor coils and fan are clean, so I had techs come give it a shot under home warranty: Trip 1 - Tech came to assess, ordered new evaporator fanTrip 2 - Replaced fresh food evaporator fan (note new fan is working in fridge, and old fan works fine on bench)Trip 3 - Ordered main computer PCBATrip 4 - Replaced main computer PCBA Unfortunately, it continues the same cycle of misreading the temperature until power cycles, and taking a day off of work for each visit is getting painful. Any ideas?
As I suspected, the unit was low on refrigerant. Apparently the firmware in the PCB satisfies the fresh food temperature and then tries to satisfy the freezer. It doesn’t seem to read the fresh food temperature during that time. If the freezer can’t actually reach temperature, the system eventually times out (not sure if it’s freezer evaporator defrost or freezer defrost?) and tends to the fridge again. Service tap was less than -10psi initially. Adding some R134a refrigerant to bring up the pressure to between 0psi and +2psi (depending on how cold things were) made things happy again.
