McQuay WSC Operating Manual page 42

Problem Alarms
The following alarms do not cause compressor shutdown but limit operation of the chiller in some way as
described in the Action Taken column. A limit alarm will trigger the red alarm screen but not the digital
output for the optional remote alarm.
Table 21, Problem Alarm Description
Description
Low Evaporator Pressure
– Inhibit Loading
Low Evaporator Pressure
– Unload
Evaporator Freeze
Protect
Condenser Freeze
Protect
High Discharge
Temperature
Warning Alarms
A warning is annunciated whenever an abnormal condition exists which does not affect chiller operation
and does not trigger the remote alarm.
Table 22, Warning Alarm Description
WARNING
Liquid Line Refrigerant
Temperature Sensor Fall Warning
Entering Evaporator Water
Temperature Sensor Fall Warning
Leaving Condenser Water
Temperature Sensor Fail Warning
Entering Condenser Water
Temperature Sensor Fail Warning
Figure 26, Keyboard
42
Display Occurs When:
Lo Evap Press- Pressure < Low Evap
NoLoad Pressure–Inhibit setpoint
Low Evap Pressure < Low Evap
Press-Unload Pressure–Unload setpoint
Evap Pres Lo- Evap Sat Refr Temp <
Freeze Evaporator Freeze SP
Cond Pres Lo- Cond Sat Refr Temp <
Freeze Condenser Freeze SP
Temperature > High Discharge
High Discharge
Temperature-Load SP AND
T-Load
Suction superheat < 15° F
DISPLAY
Liq Line T Sen Warn
Ent Evap T Sen Warn
Lvg Cond T Sen
Ent Cond T Sen
Action Taken
Evap Press rises
Inhibit loading
above (SP + 3psi)
Evap Press rises
Unload
above (SP + 3psi)
Start
Temp > (Evaporator
evaporator
Freeze SP + 2° F)
pump
Start condenser Temp > (Condenser
pump Freeze SP + 2° F)
Temp < (High Dsch
Load Temp Load SP – 3° F)
OR Superheat > 18° F
CONDITION
Sensor is shorted or open
Sensor is shorted or open
Sensor is shorted or open
Sensor is shorted or open
The keyboard is for
entering the password
when attempting to
enter or change a
setpoint. This screen
is accessed from the
SERVICE screen by
pressing the
PASSWORD button.
It is automatically
accessed when making
a change to a setpoint
on any SET screen.
Reset
OM Centrif Micro ΙΙ-5