M&M
R
EFRIGERATION
I
NC
. 3-17
Chapter 3: Oil Temperature Regulation
Oil Temperature Regulation
The oil temperature in the oil separator is regulated when the screw compressor is stopped.
The temperature is maintained above the oil heater setpoint with a deadband of +5 degrees.
When the compressor is stopped and the Oil Sump Temperature falls below the Heater Con-
trol setpoint, the oil heaters will be turned on. When the Oil Sump Temperature rises 5 degrees
above the Heater Control setpoint, the oil heaters will be turned off. The Heater Control set-
point may be found on the Oil Temperature Setpoints screen under the SETPT hot key.
Liquid Injection Oil Cooling (Option)
The RWB screw compressor may be configured for single port or dual port liquid injection
cooling. When either of the liquid injection options is installed, two additional setpoints will
appear on the oil temperature setpoint screen. The liquid injection cut-in setpoint defines the
oil temperature at which liquid injection will be started. The liquid injection cut-out setpoint
defines the oil temperature at which liquid injection will be stopped.
The RWB CCS is configured for dual port liquid injection whenever the liquid injection option is
installed. All solenoid outputs will be generated but if no solenoid is attached to the output the
signal is ignored.
Single Port Liquid Injection
Single port liquid injection uses one main injection solenoid which is opened and closed
based on oil temperature whenever the motor is running.
Dual Port Liquid Injection
Dual port liquid injection utilizes a main injection solenoid and a second solenoid to switch
between a low Vi and a high Vi injection port. The main injection solenoid is open and
closed based on temperature whenever the motor is running. The high/low Vi solenoid is
controlled based on the current Vi setting. When the Vi is above 3.5 the high/Low Vi sole-
noid is energized. When the Vi is below 3.5 the high/low Vi solenoid will be de-energized.
Both solenoids will be de-energized when the motor is stopped.
Anti-Cycle Timer
The Anti-Cycle timer is used to avoid repeated start attempts within a 20 minute period of time.
The Anti-Cycle timer is started with the motor and must completely count down before the
motor can be started again. The time period is not adjustable by the operator.
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