Scotsman NME1250R Service Manual page 17

OPERATION: Refrigeration
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.
DISCHARGE
LINE
HEAD
PRESSURE
CONTROL
VALVE
RECEIVER
LOW CONDENSING TEMPERATURE
LIQUID LINE
August 1993
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 180 psig). At that
pressure the valve opens up the liquid line from
the condenser to the receiver.
DETAIL OF HEAD
PRESSURE CONTROL
LIQUID LINE
VALVE
COMPRESSOR
Page 17
NME1250R
REMOTE CONDENSER
VALVE
THERMOSTATIC
EXPANSION
VALVE
EVAPORATOR