Johnson Controls YVAHP0721CW Series, Service Manual

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3-48
SM-16007
TROUBLESHOOTING
*1): When replacing or checking for the inverter part, make sure to perform the electric discharge work according to
Section 4.2.1.1 “High Voltage Discharge Work for Replacing Parts”.
*2): When replacing or checking for the fan controller, make sure to perform the electric discharge work according to
Section 4.2.1.1 “High Voltage Discharge Work for Replacing Parts”.
*3): When the fuse for the fan controller is blown, the fan controller may be broken too.
In this instance, the fan controller should be replaced.
Cause Check Item
Action
(Turn OFF Main Switch)
Event
Check conduction.
Check for loose
screw connections.
Replace or repair
wires, or tighten screws.
Check connection Nos.
Correctly connect wires.
Check connection.
Repair wiring
connection.
Replace PCB if faulty.
Replace power fuse,
power transistor, and
diode module.
Replace incoming
current limit resistance.
Between O.U. PCB,
Inverter PCB and
Fan Controller
Disconnected
Wires,
Contact Failure or
Incorrect
Connection Check continuity of
wires.
Check for loose
screw connections.
Check connection No.
Replace or repair
wires, tighten screws
or correct wires.
Power Source Wiring
for Outdoor Unit
Disconnected Wires
to PCB
Faulty PCB
Blown Power Fuse
Disconnected
Incoming Current Limit
Resistance
Check conduction of
power fuse, power
transistor, diode module.
Check resistance of
incoming current limit
resistance.
Disconnected Wires,
Contact Failure
Incorrect Wiring
Incorrect Wiring
Failure of
O.U. PCB,
Inverter PCB and
Fan Controller
Failure of
Electrical
Components
Power Fuse,
Resistance
Blown Fuse
(Fan Controller) Check conduction
of fuse. Replace Fan Controller
if faulty *3)