McQuay AGZ 035A, Инструкция по установке, эксплуатации и обслуживанию

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44 AGZ 035A through 065A IOMM AGZ-3
Head Pressure Control
There are two condenser fans per refrigerant circuit. These fans are cycled on and off according to
the circuit’s condenser pressure. Fan #1 of a refrigerant circuit will start when number one
compressor of that refrigerant circuit has started. This fan will not cycle off until the circuit is
stopped. The second fan on a refrigerant circuit will cycle on and off according to its head pressure
controller (PC12 or PC22).
Optional Head Pressure Control (SpeedTrol)
The first condenser fan on each circuit can have the SpeedTrol option. The fan rpm’s is varied to
maintain a minimum condenser head pressure for stable operation at low ambient temperatures. Wind
baffles can be required in addition to the SpeedTrol option for low ambient operation.
Alarms
Circuit Alarm Conditions
The “Circuit Alarm Conditions” are those alarms that only affect one circuit and can stop the
compressors of that circuit. These alarms are:
•
Compressor Motor Protection
•
High Condenser Pressure
•
Freezestat Protection
The Alarm Light on the control panel will illuminate if either circuit has a high head pressure
occurrence or a compressor motor protection occurrence. Freeze protection would be indicated on
the optional Zone Terminal. If a circuit is off and the panel alarm light is not on, try depressing the
Freezestat reset on the control panel. There is a five minute time delay after depressing the reset
button.
The chiller must have the manual reset system alarm conditions cleared before normal operation can
resume. If the alarm that occurred is an auto-clearing alarm, once the condition has corrected, the
chiller will resume normal operation provided the anti-cycle timers have cleared and sufficient load
exists.
System Alarm Conditions
The “System Alarm Conditions” are those alarms that are common to both refrigeration circuits and
require all compressors to be temporarily shut off or locked out, whichever applies.
System alarm conditions are:
•
Loss of Water Flow
•
Phase Voltage Monitor PVM (Optional)
•
Ground Fault Protection GFP (Optional)
The Alarm Light on the control panel will illuminate if either the PVM or GFP has a fault occurrence.
Loss of water flow is indicated on the optional Zone Terminal.
The chiller must have the manual reset system alarm conditions cleared before normal operation can
resume. If the alarm that occurred is an auto-clearing alarm, once the condition has corrected, the
chiller will resume normal operation provided the anti-cycle timers have cleared and sufficient load
exists.