Mitsubishi Electric PU(H)Y-P250YGM-A, Service Handbook

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[
IX
Troubleshooting ]
Flow chart
Flowchart when the MA remote controller cannot be operated
YES
No display appears on the
MA remote controller. NO
YES
NO
YES
YES
Power failure occurred
on the indoor unit
NO
Power failure occurred
on all the indoor units.
NO Turn on the power.
YES
Extinguished within
approx. 3 minutes
"HO" is displayed during the start-up
after the main power is turned on.
NO
Turn on the power.
Being displayed for
1 minute or more
YES
YES
LED 2 is lit on one of the controller
circuit boards of each indoor unit when the
daisy-wirings between the MA remote controllers
of the indoor units are disconnected.
YES
YES
Possible to operate the unit
with the MA remote controller
NO. (lit or extinguished)
Check the daisy-wirings.
NO
Normal
Including when "Centralized" is displayed
NO
NO
"6602" or "6607" errors occur
if the operation is kept going.
YES
All the LED 2 on the
controller circuit boards of
some of the indoor units
are extinguished.
YES
To the page that explains
the occurred error code
NO
To section 1.
The power of only the indoor
unit is turned ON again.
YES
YES
NO
*After the error is corrected,
reconnect the daisy-wirings of
the MA remote controller.
NO
The operation returns to
normal when the daisy-wirings
of the MA remote controller
are reconnected.
YES
Although No. 1 refrigerant circuit
is normal, No. 2 refrigerant
circuit remains stopped.
To section 2.
Check the No.1 refrigerant circuit.
Replace the MA remote controller.
NO
To section 2
NO
Check the No.2 refrigerant circuit.
Check the M-NET transmission line.
Check that the screws on the dairy-wirings
of the MA remote controller are not loose.
To section 1-2).
LED 2 are extinguished
on the controller circuit
boards of other indoor units.
Short-circuit of the
remote controller wiring
Replace the circuit board
of the indoor unit.
The MA remote controller
cannot be operated.
Running group operation with
the MA remote controller
"HO" is kept being displayed
on the MA remote controller.
To section 3.
LED 1 blinks on all the circuit
boards inside the indoor unit.
(for approx. 20-second interval)
To section 1.
Check the remote
controller wiring.