YVAA Style A Air-Cooled Screw Liquid Chillers ... - Johnson Controls

SECTION 9 - MAINTENANCE
TABLE 13 - TROUBLESHOOTING GUIDE (CONT'D)
134
PROBLEM POSSIBLE CAUSE ACTION
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
Coils dirty. Check and clean coils.
Coils are damaged. Comb out fins.
Fans NOT operating.
Check fan fuses.
Check fan rotation.
Check fan motor/blade.
FORM 201.28-NM1.1
ISSUE DATE: 8/29/2012
System is overcharged. Remove charge and check subcooling.
Discharge Temperature Sensor is defective. Check Sensor.
Condenser Fans NOT operating or are running
backwards.
Check Fans.
Coils dirty. Check and clean Coils.
High Superheat.
High Motor temperature input from one of
the sensors.
Measure Superheat with gauges and
thermocouple. Determine cause.
Low charge. Check subcooling.
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.
Transducer reads incorrectly. Check transducer against a gauge.
Suction Temp. Sensor reads incorrectly. Check sensor against a thermocouple.
Low flow. Check flow.
Condenser Drain (Flash Tank Feed) Valve
NOT operating.
Condenser or Drain (Flash Tank Feed) Valve
defective.
Check Feed and Drain Valve operation.
Check superheat.
Check Feed and Drain Valve operation.
Check superheat.
Discharge Transducer is defective. Check transducer against a gauge.
Ambient Temp. very high. Normal operation.
Fans NOT operating. Check fan operation.
Remote or local discharge pressure
load limiting is programmed.
NOTE: Always remove power to the chiller and assure the DC Bus voltage has bled off.
Normal operation.
JOHNSON CONTROLS