4
Solenoid
Valve
TXV
Expansion
Valve
Evaporator
Subcooler
TXV
Bulb
TXV
Bulb
Suction
Accumulator
(Required)
Condenser
High Efficiency
Oil Separator
(Required)
Oil Return
to Crankcase
Set for Pressure Equivalent of
No Lower than 70F SCT
Y-1037
Required
for R-22
Discharge
Pressure
Regulator
Optional Liquid Injection
TXV
LOW
LOW
HIGH
➊
➌
➍
➎
➏
➐
➋
Fig. 1 — Single Compressor System
System Operation:
1.
Suction gas from evaporator enters compressor suction manifold.
2.
The two low stage cylinder banks compress refrigerant to intermediate pressure and flow to the intermediate
manifold.
3.
A tap off the main liquid line directly expands refrigerant at condensing pressure to interstage pressure in the
subcooler.
4.
Liquid on the way to the evaporator passes through the heat exchanger and is subcooled.
5.
Cool suction gas at interstage pressure flows from the heat exchanger to the intermediate manifold (econo-
mizer port) where it is mixed with the refrigerant leaving the low stage cylinders. This mixing desuperheats the
intermediate stage refrigerant.
6.
Desuperheated refrigerant (at intermediate pressure) flows to motor compartment and then through internal
passages to high stage cylinder block.
7.
High stage cylinder compresses refrigerant and discharge to condenser.
