Thermo King T-500R Maintenance Manual page 66

Zone 1 Cool and Zone 2 Cool UT SPECTRUM Units
High pressure refrigerant vapor leaves the compressor and flows through the open CIS to the condenser where the refrigerant
releases heat and condenses into high pressure liquid. The liquid refrigerant flows through the CCV, receiver tank, and drier, into
the liquid lines.
The LLS1 is open so some of the refrigerant flows through the Zone 1 heat exchanger and expansion valve into the evaporator.
There, liquid refrigerant absorbs heat as it evaporates into low pressure vapor. The refrigerant returns to the compressor through
the heat exchanger, SLS1, suction line, SLCV1, accumulator, and ETV.
The LLS2 is also open so some of the refrigerant flows through the Zone 2 heat exchanger and expansion valve into the
evaporator. There, liquid refrigerant absorbs heat as it evaporates into low pressure vapor. The refrigerant returns to the
compressor through the heat exchanger, SLS2, suction line, SLCV2, accumulator, and ETV.
Zone 1 Evaporator
1F. Zone 1 Liquid Line Solenoid (LLS1)-Open/ Energized
2F. Zone 1 Liquid Return Check Valve (LRCV1)-Closed
3F. Zone 1 Suction Line Solenoid (SLS1)-Open/ De-energized
4F. Zone 1 Suction Line Check Valve (SLCV1)-Open
5F. Zone 1 Hot Gas Solenoid (HGS1)-Closed/ De-energized
Zone 2 Evaporator
1R. Zone 2 Liquid Line Solenoid (LLS2)-Open/ Energized
2R. Zone 2 Liquid Return Check Valve (LRCV2)-Closed
3R. Zone 2 Suction Line Solenoid (SLS2)-Open/ De-energized
4R. Zone 2 Suction Line Check Valve (SLCV2)-Open
5R. Zone 2 Hot Gas Solenoid (HGS2)-Closed/ De-energized
Condensing Unit
6. Condenser Inlet Solenoid (CIS)-Open/ De-energized
7. Liquid Injection Solenoid (LIS)-Closed/De-energized but the microprocessor will open it if necessary to control compressor
temperature.
8. Condenser Check Valve (CCV)-Open
9. Receiver Tank Pressure Solenoid (RTPS)-Closed/De-energized
10. Purge Valve (PV)-Closed/De-energized
11. Purge Check Valve (PCV)-Closed
12. Hot Gas Bypass Solenoid (HGBS)-Closed/De-energized but the microprocessor will open it if necessary to control suction
pressure.
Solenoid Delays
HGS Delay – When there is a requirement for the CIS valve to open (de-energize) and a HGS to close (de-energize), the HGS
will delay closing (de-energizing) for 5 seconds.
Unit Description 5-32