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cooler interlock failure. This alarm is generated if one of the
following criteria is met:
1. The circuit (flow switch and optional pump interlock in-
stalled at TB5-1 and 2) fails to close within the OFF to
ON delay (Configuration
2. If the unit is the lag chiller under Master/Slave Control
and the circuit fails to close within 1 minute after its
pump is commanded ON.
3. The circuit opens while the machine is ON.
4. If the remote interlock switch is CLOSED while the
machine is ON (units with EMM only).
5. If the machine is configured for Cooler Pump Control
and the circuit does not open within 2 minutes.
6. The circuit fails to close within the OFF to ON delay
when the cooler pump has been commanded ON for
freeze protection.
Action to be Taken — The unit is shut down immediately, or
not allowed to start.
Reset Method — Automatic, if the alarm occurs while the
machine is at Stage 0 (no compressors ON). Manual reset if
machine was at Stage 1 or greater.
Possible Causes — If this condition is encountered, check the
following items:
• Check the chilled water flow switch operation.
• Check for water flow. Be sure all water isolation valves
are open. Check the water strainer for a restriction.
• Check the interlock wiring circuit.
• Check for a power supply to the pump.
• Check for a control signal to the pump controller.
• Check the chilled water pump operation.
• Check the cooler pump contactor for proper operation.
P.15 — Condenser Flow Switch Failure
Criteria for Trip — Condenser flow switch has not closed
within 1 minute after condenser pump output has energized or
opens during normal operation. This alarm is for units with the
heat reclaim option only.
Action to be Taken — The unit will return to the air cooled
mode.
Reset Method — Manual.
Possible Causes — If this condition is encountered, check the
following items:
• Check the condenser water flow switch operation.
• Check for low water flow. Be sure all water isolation
valves are open.
• Check for plugged water strainer.
• Check the interlock wiring circuit.
• Check the power supply to the pump.
• Check for a control signal to the pump starter.
• Check the condenser water pump operation.
• Check the condenser pump contactor for proper
operation.
Compressor Not Started or Pressure Not Established
P.16 — Compressor A1
P.17 — Compressor A2
P.18 — Compressor A3
P.19 — Compressor A4
P.20 — Compressor B1
P.21 — Compressor B2
P.22 — Compressor B3
P.23 — Compressor B4
P.24 — Compressor C1
P.25 — Compressor C2
P.26 — Compressor C3
P.27 — Compressor C4
Criteria for Trip — The criteria are tested whether the unit is
ON or in Service Test. This algorithm monitors the pressure
OPTN
DELY).
differential across the compressor to prove proper rotation of
the compressor.
During normal operation with the start of a compressor, the
discharge pressure for the circuit or the compressor differential
(Discharge Pressure – Suction Pressure) must increase 10 psig
(69 kPa) after 2 minutes. If this criterion is not met, the alarm is
generated.
Action to be Taken — The circuit is shut down immediately.
Reset Method — Manual
Possible Causes — If this condition is encountered, check the
following items:
• Check for power to the compressor.
• Check control voltage to the compressor contactor. On
208-volt systems, be sure the proper tap on TRAN1 is
utilized.
• Check for proper electrical phasing of the unit power
supply.
• Check the compressor contactor operation.
• Check the discharge and suction pressure transducers for
accuracy.
• Check the wiring and location of the discharge and suc-
tion pressure transducers.
P.28 — Electrical Box Thermostat Failure/Reverse Rotation
Criteria for Trip — The criterion is tested whether the unit is
ON. This alarm is generated if the signal is open.
Action to be Taken — The unit is not allowed to start.
Reset Method — Automatic, once the phasing is corrected.
Possible Causes — If this condition is encountered, check the
following items:
• Check the power wiring for proper phasing.
• Check the sensor wiring to reverse rotation protection
board.
P.29 — Loss of Communication with System Manager
Criteria for Trip — The criterion is tested whether the unit is
ON or OFF. This alarm is generated if the System Manager
had established communications with the machine and is lost
for more than 2 minutes.
Action to be Taken — The action to be taken by the control
depends on the configuration. If Auto Start when SM lost is
enabled, (Configuration
unit will force the CCN Chiller Start Stop (Run Status
R.CCN
CH.SS) to ENBL and clear all forced points
from the System Manager. The unit will revert to stand-alone
operation.
Reset Method — Automatic, once communication is
re-established.
Possible Causes — If this condition is encountered, check the
following items:
• Check communication wiring.
• Check the power supply to the System Manager and unit
controls.
P.30 — Master/Slave Communication Failure
Criteria for Trip — The criterion is tested whether the units are
ON or OFF and a Master and Slave machine has been config-
ured, (Configuration
RSET
MSSL=2). If communication is lost for more than
3 minutes, this alarm is generated.
Action to be Taken — Dual chiller control will be disabled and
each unit will operate in Stand-Alone mode.
Reset Method — Automatic, once communication is
re-established.
Possible Causes — If this condition is encountered, check the
following items:
• Check the CCN wiring.
• Check for control power to each Main Base Board,
Master and Slave.
68
SERV
AU.SM=YES), then the
RSET
MSSL=1 and Configuration
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