Thermo King UT-1200, Manual

Page: 34 / 169

Unit Description
34
Cool Mode
The refrigerant flow in Cool Mode is a
conventional refrigeration cycle. 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 condenser check valve, receiver tank,
drier, heat exchanger, and the 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, and accumulator.
Solenoid and Check Valves
1. Condenser Inlet Solenoid (CIS)-Open/
De-energized
2. Liquid Injection Solenoid (LIS)-Closed/
De-energized but the microprocessor will
open it if necessary to control compressor
temperature.
3. Condenser Check Valve-Open
4. Receiver Tank Pressure Check Valve-Closed
5. Purge Valve (PV)-Closed/De-energized
6. Purge Check Valve-Closed
7. Hot Gas Solenoid (HGS)-Closed/
De-energized
Figure 7: Cool Mode
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