True commercial refrigerator not cooling

[CCRUZ]

Model Number

TUC-72

Brand

Age

1-5 years

True TUC-72 commercial/restaurant refrigerator only cooling to approximately 60-65°F. Unit is 1.5yrs old, we noticed when compressor was continuously running.

Compressor is functioning. Condenser fan is operating, condenser coils are clean. Both (2) evaporator fans are operating. Unit has (3) doors and all seals are intact and in good condition, perimeter heater is functioning.

I measured capillary temperature into evaporator of 38-40°F and compressor suction of 68-70°F. Temperature control will turn the compressor off at approximately 60°F, all other settings (2 thru 9) cause it to run continuously.

Any ideas or help would be greatly appreciated. Thanks in advance.

 

[rickgburton]

Sounds like a sealed system issue. Possibly a small leak or partial restriction. Check your warranty. It should be covered. Call True and set up a warranty service call.

 

[CCRUZ]

I checked the refrigerant charge, it was pretty close to vacuum. I have searched and seen people charging standard residential models to 3-5psi, I have also seen commercial GE models run with 20psi.

I installed a piercing valve and charged the unit until the cabinet temperature decreased/increased, then recovered excess to bring temperatures back down. I ended up around 23psi. Compressor is tagged for 8A and running at 7.8-8.0A so I wouldn't think I'm flooded/overfilled yet.

The unit is running now, I am going to see where it ends up. I haven't seen any deviations in the pressure at the piercing valve.

I know the unit may be under warranty but I absolutely hate dealing with manufacturers.

 

[rickgburton]

...I ended up around 23psi.

Way too high! Use a pressure temperature chart or risk damaging the compressor.

 

[CCRUZ]

Rick, thanks for the response.

What I am looking at shows ~25psi for 30°F, am I missing something? Refrigerant is R134a.

When the problem originally occurred we noticed because the compressor was running continuously, now that the unit is cooling it still will not cycle off.

I pulled the temperature control switch (from the evaporator) and submerged the sensing element in cold media and the state of the switch didn't change no matter the setting. So now I need a new one of those as well.