McQuay AWS User Manual

KOMAC00607-09EN 41
Reset: This alarm can be cleared manually if the evaporator pressure is above –10
psi.
Low Pressure Start Fail
Alarm description (as shown on screen): LowPressStartFail N
Trigger: Circuit state = start for time greater than Startup Time set point.
Action Taken: Rapid stop circuit
Reset: This alarm can be cleared manually via the Unit Controller keypad
Mechanical Low Pressure Switch
Alarm description (as shown on screen): Mech Low Pressure Sw N
Trigger: Mechanical Low Pressure switch input is low
Action Taken: Rapid stop circuit
Reset: This alarm can be cleared manually via the Unit Controller keypad if the
MLP switch input is high.
High Condenser Pressure
Alarm description (as shown on screen): Cond Pressure High N
Trigger: Condenser Saturated Temperature > Max Saturated Condenser Value for
time > High Cond Delay set point.
Action Taken: Rapid stop circuit
Reset: This alarm can be cleared manually via the Unit Controller keypad
Low Pressure Ratio
Alarm description (as shown on screen): Low Pressure Ratio N
Trigger: Pressure ratio < calculated limit for a time > Low Pressure Ratio Delay
set point after circuit startup has completed. The calculated limit will vary from 1.4
to 1.8 as the compressor’s capacity varies from 25% to 100%.
Action Taken: Normal shutdown of circuit
Reset: alarm can be cleared manually via the Unit Controller keypad
Mechanical High Pressure Switch
Alarm description (as shown on screen): Mech High Pressure Sw N
Trigger: Mechanical High Pressure switch input is low AND Emergency Stop
Alarm is not active.
(opening emergency stop switch kills power to MHP switches)
Action Taken: Rapid stop circuit
Reset: This alarm can be cleared manually via the Unit Controller keypad if the
MHP switch input is high.
High Discharge Temperature
Alarm description (as shown on screen): Disc Temp High N
Trigger: Discharge Temperature > High Discharge Temperature set point AND
compressor is running. Alarm cannot trigger if discharge temperature sensor fault
is active.
Action Taken: Rapid stop circuit
Reset: This alarm can be cleared manually via the Unit Controller keypad.
High Oil Pressure Difference
Alarm description (as shown on screen): Oil Pres Diff High N
Trigger: Oil Pressure Differential > High Oil Pressure Differential set point for a
time greater than Oil Pressure Differential Delay.
Action Taken: Rapid stop circuit
Reset: This alarm can be cleared manually via the Unit Controller keypad.

McQuay AWS Specifications

General

Brand	McQuay
Model	AWS
Category	Chiller
Language	English