Service manual

Part No. 80-1100-3 7-1
Section 7
Refrigeration System
Sequence of Operation
SELF-CONTAINED AIR OR WATER -COOLED MODELS
Figure 7-1. Self-Contained Prechill and Freeze Cycle
(Models Q200/Q280/Q320/Q370/Q420/Q450/Q600/Q800/Q1000)
Prechill Refrigeration Sequence
No water flows over the evaporator during the prechill.
The refrigerant absorbs heat (picked up during the
harvest cycle) from the evaporator. The suction pressure
decreases during the prechill.
Freeze Cycle Refrigeration Sequence
The refrigerant absorbs heat from water running over the
evaporator surface. The suction pressure gradually
drops as ice forms.
HEAT
EXCHANGER
EVAPORATOR
CONDENSER
COMPRESSOR
EXPANSION VALVE
HARVEST SOLENOID VALVE
AIR OR WATER
DRIER
STRAINER
RECEIVER
(WATER COOLED ONLY)
LOW PRESSURE VAPORLOW PRESSURE LIQUIDHIGH PRESSURE LIQUID
H
IGH PRESSURE VAPOR
X
SV1569