Mitsubishi Electric CAHV-P500YA-HPB, Service Handbook

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[
IX
Troubleshooting ]
- 113 -
HWE10060 GB
[2] Troubleshooting
Troubleshooting according to the remote controller malfunction or the external input error
Both for MA remote controller and ME remote controller
1. If a problem occurs, please check the following. If a protection device has tripped and brought the unit to stop (when an error
code is blinking on the LED), resolve the cause of the error before resuming operation.
Resuming operation without removing the causes of an error may damage the unit and its components.
Problem Check item Cause Solution
The unit does not
operate.
The fuse in the control
box is not blown.
The power lamp on the
circuit board is not lit.
The main power is not turned on. Switch on the power.
The power lamp on the
circuit board is lit.
The pump interlock circuit is not con-
nected.
Connect the pump interlock circuit wiring to
the system.
The flow switch wiring is not connect-
ed.
Connect the flow switch wiring to the sys-
tem.
The fuse in the control
box is blown.
Measure the circuit
resistance and the
earth resistance.
Short-circuited circuit or ground fault Resolve the cause, and replace the fuse.
The compressor does
not operate.
Protection devices
have not tripped.
INV board problem Repair or replace the INV board.
Noise filter board problem Repair or replace the noise filter board.
High-pressure cutout
switch has tripped.
AHP1
Abnormal
high
pressure
Dirty condenser
(scaling formation)
Clean the condenser.
Air in the refrigerant circuit Vacuum the refrigerant circuit, and charge
it with refrigerant.
Water flow shortage Secure enough water flow rate.
The discharge
temperature thermistor
has tripped.
AC61
LEV fault in the main circuit Replace the LEV in the main circuit.
Injection LEV fault Replace the injection LEV.
Injection solenoid valve fault Replace the solenoid valve.
Refrigerant gas leakage Leakage test
Refrigerant undercharge Repair the cause of refrigerant shortage,
evacuate the system, and charge the refrig-
erant circuit with refrigerant.
A thermistor error was
detected.
5101~5115
Broken or short-circuited thermistor
wiring
Check the thermistor wiring for broken con-
nections or short circuit.
Replace the thermistor.
Overcurrent passed
through the compres-
sor.
4250
Compressor motor Replace the compressor.
Overload operation Check the operation patterns.
Seized compressor shaft Replace the compressor.
The pump interlock has
tripped.
The pump interlock circuit is not con-
nected.
Connect the pump interlock wiring.
The water pump is not operating. Operate the pump.
Problem with the solenoid contactor for
the pump
Replace the solenoid contactor.
The flow switch has
tripped.
The flow switch wiring is not connect-
ed.
Connect the flow switch wiring to the sys-
tem.
Water flow shortage Increase the water flow rate.
Flow switch contact failure Polish the contact point.
Automatic Start/Stop
thermistor has tripped.
The water temperature has reached
above the preset temperature.
Normal
The motor whines, but
will not turn.
Contact failure at a connector terminal Polish the contact point.
Loose wire connection Tighten the wire connection.
Seized compressor or fan bearing Disassemble the compressor or the fan,
and repair as necessary.
High-pressure is too high. Check the operation patterns.
A momentary overcur-
rent was detected.
Burned, short-circuited, or ground
faulted motor
Replace the compressor, and clean the re-
frigerant circuit.