56
OM
AGSD-1
pLAN Failure
Alarm description (as shown on screen):
pLan Failure
Trigger:
pLAN communication from one controller to the other is lost. Only applies to
three circuit chillers.
Action Taken:
Rapid stop circuit #3
Reset:
This alarm automatically resets when communication with the unit controller is
established. This alarm is not logged.
Circuit Events
The following events limit operation of the circuit in some way as described in the Action
Taken section. The occurrence of a circuit event only affects the circuit on which it
occurred. Circuit events are logged in the event log on the unit controller.
Low Evaporator Pressure - Hold
Event description (as shown on screen):
EvapPress Low Hold N
Trigger:
The low pressure events are not enabled until the compressor has started and the
evaporator pressure has risen above the Low Evaporator Pressure - Hold setpoint. The unit
mode must also be Cool. Then, while running, if evaporator pressure <= Low Evaporator
Pressure - Hold setpoint the event is triggered.
Action Taken:
Inhibit loading by only allowing the slide target to be reduced.
Reset:
While still running, the event will be reset if evaporator pressure > (Low Evaporator
Pressure - Hold SP + 2psi). The event is also reset if the unit mode is switched to Ice, or the
compressor state is no longer Run.
Low Evaporator Pressure - Unload
Event description (as shown on screen):
EvapPressLowUnload N
Trigger:
The low pressure events are not enabled until the compressor has started and the
evaporator pressure has risen above the Low Evaporator Pressure - Hold setpoint. The unit
mode must also be Cool. Then, while running, if evaporator pressure <= Low Evaporator
Pressure - Unload setpoint the event is triggered.
Action Taken:
Unload the compressor by decreasing the slide target 5% every five seconds
until the evaporator pressure rises above the Low Evaporator Pressure – Unload setpoint.
Reset:
While still running, the event will be reset if evaporator pressure > (Low Evaporator
Pressure - Hold SP + 2psi). The event is also reset if the unit mode is switched to Ice, or the
compressor state is no longer Run.
High Lift Pressure - Hold
Event description (as shown on screen):
LiftPressHigh Hold N
Trigger:
While the compressor is running and unit mode is Cool, if saturated condenser
temperature >= High Saturated Condenser - Hold Value, the event is triggered.
Action Taken:
Inhibit loading by only allowing the slide target to be reduced.
Reset:
While still running, the event will be reset if saturated condenser temperature <
(High Saturated Condenser - Hold Value – 10
o
F). The event is also reset if the unit mode is
switched to Ice, or the compressor state is no longer Run.
Summary of Contents for AGS 225D
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