Refrigeration Cycle

Pressure Relief Valve:

REFRIGERANT FLOW
The refrigerant flow is in the standard pattern. Refrigerant flows through the compressor, condenser, liquid tank, evaporator and back to the compressor.
The refrigerant evaporation through the evaporator coil is controlled by an externally equalized expansion valve, located inside the evaporator case.

FREEZE PROTECTION
The compressor cycles on and off to maintain the evaporator temperature within a specified range. When the evaporator coil temperature falls below a specified point, the thermo control amplifier interrupts the compressor operation. When the evaporator coil temperature rises above the specification, the thermo control amplifier allows compressor operation.

REFRIGERANT SYSTEM PROTECTION

Dual-pressure switch
The dual-pressure switch is located on the liquid tank. If the system pressure rises or falls out of specifications, the switch opens to interrupt compressor clutch operation.

Pressure relief valve
The refrigerant system is protected by a pressure relief valve. The valve is located on the compressor near the thermal protector. When refrigerant system pressure increases abnormally [over 3.727 kPa (38 kg/Sq. cm, 540 psi)], the relief valve port opens. The valve then releases refrigerant into the atmosphere. The relief valve port closes when pressure reaches 2.991 kPa (30.5 kg/Sq. cm, 434 psi).