Electrical, Refrigeration and
µ
P-D Menu Flow Diagrams
Refrigeration Schematic: Modulation Cool
9-39
CRR-20 & CRR-40, September 1999
Flow and Pressure Diagram
CRR-20 & CRR-40
Modulation Cool
17.
Liquid Line Solenoid (LLS)
Is a normally CLOSED solenoid.
It OPENS when energized, when the compressor operates.
23.
Electric Heaters
During the DEFROST mode, the electric heaters are pulsed ON and OFF.
The compressor does not operate. The condenser fan and evaporator fans
remain OFF.
During the HEAT mode, the electric heaters are pulsed ON and OFF. The
compressor does not operate. The condenser fan is OFF. The evaporator
fans continue to operate (evaporator fan speed is determined by return air
temperature and economy mode setting).
30.
Evaporator Pressure Regulator (KVQ Valve)
Is a normally OPEN actuator valve. It CLOSES (or OPENS) according to
the strength and frequency of a pulsing voltage signal from the controller.
The voltage signal energizes a heating element in the actuator power ele-
ment. Increasing the temperature of the heating element increases the
pressure on the main valve actuator, forcing the valve towards the closed
position. Decreasing the temperature of the heating element decreases the
pressure on the main valve actuator, drawing the valve towards the open
position.
32.
Liquid Injection Valve (LIV)
Is a normally CLOSED valve.
It OPENS when energized. When liquid injection is required, the valve is
pulsed open and closed on a 10 second cycle.
Liquid injection is controlled by the compressor discharge temperature.
High pressure gas
High pressure liquid
Low pressure gas
Low pressure liquid
Condensing high pressure gas
Low pressure vaporizing liquid
Liquid refrigerant injection
Modulated pressure
Summary of Contents for CRR-20
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