Carrier PIC 5+ User Manual page 37

Alarm
Description of the alarm text Reset type
code*
Alm-233 ALM-233 Prestart Failure - Low
Refrigerant Temp
Alm-234 ALM-234 Prestart Failure - Low
Line Voltage
Alm-235 ALM-235 Prestart Failure - High
Line Voltage
Alm-236 ALM-236 Guide Vane 1
Calibration Not Completed
Alm-237 ALM-234 Prestart Failure – No
Power Supply
Alm-238 ALM-238 Guide Vane 2
Calibration Not Completed
Alm-239 ALM-239 Envelope Control
Valve Calibration Not Completed
Protective limit
Alm-250 ALM-250 Protective Limit - Oil
Pressure Difference Failure
Alm-251 ALM-251 Protective Limit - Low
Chilled Water Flow
Alm-252 ALM-252 Protective Limit - Low
Condenser Water Flow
Alm-253 ALM-253 Protective Limit - High
Discharge Temp
Alm-254 ALM-254 Protective Limit - Low
Evap Refrigerant Temp
Alm-255 ALM-255 Protective Limit - High
Motor Temperature
Action taken by the
control
As above As above
As above As above
As above As above
As above As above
As above As above
As above As above
As above As above
Manual Unit shuts down.
As above As above
As above As above
As above As above
As above As above
As above As above
Possible cause
Check Evaporator Pressure, Evap Sat Rrefig Temp, and Evap Rrefig
Liquid Temp.
Check Evaporator Pressure transducer and Evaporator Refrigerant
Liquid Temperature sensor wiring and accuracy.
Check for low chilled water supply temperatures.
Check refrigerant charge.
Check REFRIG OVERRIDE DELTA T and EVAP REFRIG TRIPPOINT
in configuration screen.
Check ACTUAL LINE VOLTAGE.
Check UNDERVOLTAGE THRESHOLD in ISM_CONF screen.
Check voltage supply. Check wiring to ISM J3-L1, J3-L2, and
J3-L3.
Check voltage transformers and switch gear.
Consult power utility if voltage is low.
Check ACTUAL LINE VOLTAGE.
Check OVERVOLTAGE THRESHOLD in ISM_CONF screen.
Check voltage supply.
Check voltage transformers and switch gear.
Consult power utility if voltage is high.
Guide Vane 1 Calibration in Quick Calibration screen.
Check guide vane actuator feedback potentiometer and wiring to IOB
connector.
Check the Power Request Output and the Power Feedback input
status.
Guide Vane 2 Calibration in Quick Calibration screen.
Check guide vane actuator feedback potentiometer and wiring to IOB
connector.
Envelope control valve Calibration in Quick Calibration screen.
Check EC valve feedback potentiometer and wiring to IOB connector.
Check oil pump
Check oil filter
Check oil pump wiring
Perform Chilled Water pump test in Quick Test screen.
Check Evap Refrig Liquid Temp and Leaving CHILLED WATER
temperature sensor accuracy and wiring to IOB.
Check chilled water valves, pumps, and strainers.
Check EVAP REFRIG TRIPPOINT, EVAP APPROACH ALERT, EVAP
FLOW DELTA P CUTOUT, and WATER FLOW VERIFY TIME settings.
Check load resistors, optional water flow switches or water flow delta
P transducer calibration and wiring to IOB.
Check for 5.0 V reference voltage between IOB connectors.
Perform Condenser Water pump test in Quick Test screen. Check
CONDENSER PRESSURE transducer and LEAVING CONDENSER
WATER temperature sensor accuracy and wiring.
Check condenser water valves and strainers.
Check COND PRESS OVERRIDE, COND APPROACH ALERT, COND
FLOW DELTA P CUTOUT, and WATER FLOW VERIFY TIME settings.
Check load resistors, optional water flow switches or water flow delta
P transducer calibration and wiring to IOB.
Check for 5.0 V reference voltage between IOB connectors.
Check for closed compressor discharge isolation valve.
Check if chiller was operating in surge conditions.
Check COMP DISCHARGE TEMP sensor resistance or voltage drop.
Check for proper wiring to IOB connectors.
Check for proper condenser flow and temperature.
Check for proper inlet guide vane and optional diffuser actuator
operation.
Check for COMP DISCHARGE TEMP > 220 deg F.
Check for fouled tubes, plugged water strainers, or non-condensable
in the condenser.
Check for proper refrigerant charge.
Check float valve operation.
Check for closed condenser liquid line isolation valve.
If problem occurs at high load, check for low condenser pressure which
causes inadequate refrigerant flow through condenser flasc orifices.
Check for proper chilled water flow and temperature. Confirm that
condenser water enters bottom row of condenser tubes first, reversed
condenser water flow may cause refrigerant to stack in the condenser.
Check EVAPORATOR PRESSURE transducer and EVAP REFRIG
LIQUID TEMP and LEAVING CHILLED WATER sensors. Check for
division plate gasket bypass.
Check for fouled tubes.
Check pressure transducer and temperature sensor wiring to the IOB.
Check COMP MOTOR WINDING TEMP accuracy and wiring to IOB.
Check motor cooling line and spray nozzle for proper operation, or
restrictions.
Check motor cooling filter/drier and isolation valves.
Look for refrigerant flow through motor cooling line sight glass.
Check for excessive starts within a short time span.
37