A reach-in freezer with hot gas defrost has frost only on the last pass of the evaporator. This indicates: a) Undercharge of refrigerant b) Defrost termination failed open c) TXV stuck open d) Non-condensables in the system
The maximum allowable refrigerant leak rate per year for commercial refrigeration under EPA Section 608 (with 50+ lb charge) is: a) 15% b) 20% c) 25% d) 35% Section 5: Safety & Best Practices 13. When recovering refrigerant from a system with a burned-out compressor, you should: a) Recover into the same tank as good refrigerant b) Use a filter drier in the recovery line c) Vent the non-condensables to speed recovery d) Skip recovery if the system is under 5 lbs
Superheat is measured at the: a) Condenser outlet b) Evaporator outlet c) Receiver inlet d) Compressor discharge
A defrost termination thermostat is wired in series with the: a) Evaporator fans b) Compressor contactor coil c) Defrost heater d) Liquid line solenoid Section 3: Troubleshooting & Diagnostics 7. A walk-in cooler has low suction pressure, low superheat, and a starved evaporator. The most likely cause is: a) Overcharge of refrigerant b) Liquid line restriction c) Bad compressor valves d) High evaporator fan speed