Johnson Controls YVAHP0721CW Series, Service Manual

Page: 256 / 416

SM-16007
TROUBLESHOOTING
Cause Check Item
Action
(Turn OFF Main Switch)
Event
Check for continuity
after temperature of
outdoor fan motor
decreases.
Faulty
Internal
Thermostat
Replace outdoor fan
motor.
Failure
Measure resistance
with a tester. Tighten or replace
connector. Contact
Failure
Check connection. Connect it correctly.
Incorrect
Connection
Excessively
Low Suction
Pressure
(in Vacuum)
Internal
Thermostat for
Outdoor Fan
is Activated
in Heating
Operation
Measure coil resistance
and insulation resistance. Replace outdoor fan
motor if faulty.
Faulty Outdoor Fan Motor
Check charged ref.
volume or check for
leakage.
Repair leakage and
correctly charge ref.
Shortage of Refrigerant
Check electrical
system and ref. cycle.
Correctly connect
indoor unit and
outdoor unit. Incorrect Connection
between Indoor Unit and
Outdoor Unit
Check connector
for O.U. PCB. Replace pressure
sensor if faulty. Abnormal Low or High
Pressure Sensor
Check stop valve. Open stop valve. Closed Stop Valve
Check Td thermistors
for compressors and
measure Td thermistor
resistance.
Repair or replace
Td thermistor. Expansion Valve Closed by
Disconnecting Td Thermistor
Check connector for
O.U. PCB.
Repair connector for O.U.
PCB or expansion valve.
Replace it if faulty.
Locked Expansion Valve
(Fully Closed)