Scotsman NM1250R - Manual (Page 20)

OPERATION:
Beginning at the compressor, the refrigerant
502 is compressed into a high temperature
gas. The discharge line directs this gas to the
condenser and to the head pressure control
At the remote condenser the gas is cooled
by air and it then condenses into a liquid. This
high pressure liquid then goes through the
liquid line to the liquid line connection at the
head pressure control. If the head pressure
is high enought the liquid refrigerant will go
through the valve and enter the receiver.
From the receiver, the liquid refrigerant flows
through the liquid line valve and then to the
expansion valve. The thermostatic expansion valve meters
liquid refrigerant into the evaporator, the
volume of liquid refrigerant depending upon
the temperature of the evaporator; warmer
evaporators get more refrigerant and colder
evaporators get less. At the evaporator, the
refrigerant enters an area of relatively low
pressure, where it can easily "boil off" or
evaporate. As it evaporates, it absorbs heat
from the evaporator and whatever is in contact
with it (such as the water inside it). After the
evaporator, the refrigerant, now a low
pressure vapor, goes through the suction line
back to compressor, where the cycle is
repeated.
REMOTE CONDENSER
DETAIL OF HEAD
PRESSURE CONTROL
VALVE
LIQUID LINE
VALVE
THERMOSTATIC
EXPANSION
VALVE
EVAPORATOR
COMPRESSOR
HIGH PRESSURE
CONTROL SWITCH
RECEIVER
HEAD
PRESSURE
CONTROL
VALVE
DISCHARGE
LINE
LIQUID LINE
NM1250R
November, 1988
Page 20