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(Always remove power to the chiller and assure the DC bus voltage has bled off)
PROBLEM
System Fault:
HIGH
DISCHARGE
PRESSURE
System Fault:
HIGH
DISCHARGE
TEMPERATURE
System Fault:
HIGH MOTOR
TEMPERATURE
System Fault:
LOW
SUCTION
PRESSURE
System Fault:
DISCHARGE
PRESSURE
LIMITING
JOHNSON CONTROLS
TROUBLESHOOTING GUIDE (CON'T)
POSSIBLE CAUSE
Coils dirty.
Coils are damaged.
Fans NOT operating.
System is overcharged.
Discharge Temperature
Sensor is defective.
Condensor Fans NOT operating
or are running backwards.
Coils dirty.
High Superheat.
High Motor temperature
input from one of the sensors
Low charge.
Transducer reads incorrectly.
Suction Temp. Sensor
reads incorrectly.
Low flow.
Feed or Drain Valve NOT operating
Feed or Drain Valve defective.
Discharge Transducer is defective.
Ambient Temp. very high.
Fans NOT operating.
Remote or local discharge pressure
load limiting is programmed.
FORM 201.21-NM1 (1223)
ACTION
Check and clean coils.
Comb out fins.
Check fan fuses.
Check fan rotation.
Check fan motor/blade.
Remove charge and check subcooling.
Check Sensor.
Check Fans.
Check and clean Coils.
Measure Superheat with guages and
thermocouple. Determine cause.
Refrigerant charge low.
Check subcooling.
Excess charge in system,
High discharge pressure.
Check subcooling.
High Superheat. Drain/Feed Valves
NOT controlling. Isolate cause.
Motor Sensor reading incorrectly.
Program panel to ignore
a single sensor.
Economizer Solenoid energized at
low speeds. Valve is leaking through.
Check subcooling.
Check transducer against a guage.
Check sensor against
a thermocouple.
Check flow.
Check Feed and Drain Valve
operation.
Check superheat.
Check Feed and Drain Valve
operation.
Check superheat.
Check transducer against a gauge.
Normal operation.
Check fan operation.
Normal operation.
9 9
295
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