Scotsman NME654R - Manual (Page 19)

OPERATION: Refrigeration
Low Condensing Temperature
The refrigeration system under low condenser air
temperatures is much the same as it is under
higher temperatures, with the exception that the
resulting low head pressures cause the head
pressure control to close off the liquid line between
the condenser and the receiver.
This forces more refrigerant into the condenser
(with a small amount of discharge gas going into
the receiver to maintain pressure until the head
pressure is built back up to the rated gauge
pressure of 180 PSIG). At that pressure the valve
opens up the liquid line from the condenser to the
receiver.
NME654R & FME804R
January 2000
Page 19
LIQUID LINE
VALVE
THERMOSTATIC
EXPANSION
VALVE
SUCTION
LINE
KING
VALVE
Refrigeration Schematic
COMPRESSOR
RECEIVER
HEAD
PRESSURE
CONTROL
VALVE
LIQUID LINE
DISCHARGE
LINE
DETAIL OF HEAD
PRESSURE CONTROL
VALVE
REMOTE CONDENSER
EVAPORATOR