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Mitsubishi Electric CAHV-P500YA-HPB Service Handbook Page 140

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[ IX Troubleshooting ]
(3) Trouble treatment when the main power breaker is tripped
Items to be checked
[1]
Check the breaker capacity.
[2]
Perform Meg check between the
terminals on the power terminal
block TB4.
[3]
Turn on the power again and
check again.
[4]
Turn on the outdoor unit and check
that it operates normally.
(4) Trouble treatment when the main power earth leakage breaker is tripped
Items to be checked
[1]
Check the earth leakage breaker
capacity and the sensitivity cur-
rent.
[2]
Check the resistance at the power
supply terminal block with a meg-
ger.
[3]
Disconnect the compressor wir-
ings and check the resistance of
the compressor with a megger.
[4]
Disconnect the fan motor wirings
and check the resistance of the fan
motor with a megger.
The insulation resistance could go down to close to 1Mohm after installation or when the power is kept off for an extended
period of time because of the accumulation of refrigerant in the compressor. If the earth leakage breaker is triggered, please
use the following procedure to take care of this.
Disconnect the wires from the compressor's terminal block.
If the resistance is less than 1 Mohm, switch on the power for the outdoor unit with the wires still disconnected.
Leave the power on for at least 12 hours.
Check that the resistance has recovered to 1 Mohm or greater.
Earth leakage current measurement method
For easy on-site measurement of the earth leakage current, enable the filter with a measurement instrument that has filter
functions as below, clamp all the power supply wires, and measure.
Recommended measurement instrument: CLAMP ON LEAK HiTESTER 3283 made by HIOKI E.E. CORPORATION
When measuring one device alone, measure near the device's power supply terminal block.
HWE10060
Phenomena
Use of a non-specified break-
er
Zero to several ohm, or Meg
failure
1) Main power breaker trip
2) No remote control display
1) Operates normally without
tripping the main breaker.
2) Main power breaker trip
Phenomena
Use of a non-specified earth
leakage breaker
Failure resistance value
Failure compressor if the insu-
lating resistance value is not in
specified range.
Failure when the insulating re-
sistance value is 1 Mohm or
less.
Failure fan motor if the insulat-
ing resistance value is not in
specified range.
Failure when the insulating re-
sistance value is 1 Mohm or
less.
- 133 -
Remedy
Replace it with a specified breaker.
Check each part and wiring.
*Refer to (5) "Simple checking procedures
for individual components of main inverter
circuit".(page 134)
IGBT module
Rush current protection resistor
Electromagnetic relay
DC reactor
a) The wiring may have been short-circuit-
ed. Search for the wire that short-circuit-
ed, and repair it.
b) If item a) above is not the cause of the
problem, refer to (2)-[1]-[6].
Remedy
Replace with a regulation earth leakage
breaker.
Check each part and wiring.
*Refer to (5) "Simple checking procedures
for individual components of main inverter
circuit".(page 134)
IGBT module
Rush current protection resistor
Electromagnetic relay
DC reactor
Check that there is no liquid refrigerant in
the compressor. If there is none, replace
the compressor.
Replace the fan motor.
GB

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