15
During the dilution cycle Refrigerant Dump Valve 1 (RDV1)
opens. Once opened, RDV1 remains open until the dilution
cycle is completed, or the machine is restarted after power
failure, or
control reset.
The operator can abort the dilution cycle to restart the unit
by pressing the auto key to restart. The chiller will restart if
the LEAVING WATER TEMPERATURE is greater than the
differential to start set point.
If a reset is performed during the dilution cycle, and there is
dilution time remaining the dilution cycle will be continued.
Normal Stop
Press the stop key for a machine stop mode. The alternate
methods to stop are the External stop input and remote
clear language display (CLD) “Stop”. Reaching the
differential to stop chilled water setpoint is another
condition that results in a shutdown sequence and is
followed by a restart when the differential to start chilled
water set point is reached.
The stop mode shutdown sequence is as follows:
When the CLD stop command is initiated, the burner is
driven to low fire. A 30-second run unloaded delay, allows
the burner to move to low fire, from a high fire position,
before the burner start command is removed.
The solution pumps are automatically adjusted to 75% of
their allowable operating range during the dilution cycle.
The condenser water and evaporator refrigerant pumps are
cycled off.
The chilled water pump remains on through the dilution
cycle and until the CLD adjusted CHWP time delay expires.
When the dilution cycle is complete, the machine solution
pumps and ventilation fan are stopped. The RDV1, which
opened when the dilution cycle started, remains open until
the machine is restarted. The CLD displays stop with the
completion of the dilution cycle.
Panic Stop
Panic Shutdown (Pressing the Stop key twice within 5
Second Interval initiates a machine panic stop)
NOTE: This is not to be used unless absolutely necessary.
Failure to properly dilute lithium bromide can crystallize the
chiller.
Panic stop can only be exited at the local CLD. When a
panic stop is initiated the following events occur:
- The machine solution pumps are stopped immediately
and without a DILUTION cycle.
- The chilled water pump (CHWP) and cooling water pump
(CWP) are also commanded off immediately.
- The Refrigerant Dump valve (RDV1) is opened to dilute the
lithium bromide in the absorber with refrigerant.
- The Ventilator fan is stopped.
- The Energy input start command is removed, stopping
the burner.
- The CLD will display “Panic Shutdown”
To exit Panic Shutdown either press AUTO or STOP.
Pressing the STOP key will initiate a dilution cycle. Pressing
the AUTO key will allow a chiller restart.
The chiller will then resume normal operation assuming
that the panic condition was corrected prior to restart.
Safety Reset
If the operator performs “Reset” during the dilution cycle,
the control remembers the amount of time remaining in
the current dilution cycle. Once the reset is complete, the
dilution cycle will be re-entered automatically. If the
machine was operating when a safety shutdown occurred
the machine will resume normal operation after resetting
the CLD.
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