Hello friends, Need some help with a freezer that i cant get to pull down to temp ( -20F)
The freezer has been working fine until last week and starting loosing temperature . Air flow is good across evaporator and is clean, all fans working. It has 2 txv valves shared by one common liquid and suction line.1 txv valve is in the middle of freezer right at the inlet of suction and liquid line entering freezer from out side, the other txv valve is located at the very end of freezer. The refrigerant is 404A. Here are some temp and pressures that i have.
The freezer box temp right now is 20(F) It was keeping -20(F)
Outside air temperature is 36(F)
suction line at compressor 22psi
liquid line at compressor 90psi
suction line temp at compressor 29(F)
liquid line temp discharging out of compressor 101(F)
liquid line temp after condensor 45(F)
suction line temp at evaporator 22(F)
suction line pressure at evaporator 20 psi
I think the charge is a little high but, when i get the suction line pressure around 15psi, you can here the lines in the freezer hissing. At current suction line pressure you can here one txv still hissing. I have taken apart and cleaned the screens but still same result. The site glass has a steady flow and no flashing or bubbles can be seen.
Any suggestions on what is wrong and how to fix? thanks for your help