Mitsubishi Electric PUMY-P112VKM5-ERBS, Техническое и сервисное руководство

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Check code
Abnormal points and detection methods Causes and checkpoints
The purpose of the check code is to prevent indoor unit from freezing or
dew condensation which is caused when a refrigerant keeps flowing into
the unit in STOP.
When all of the following conditions have been satisfied:
1. The compressor is operating in COOL mode.
2. 15 minutes have passed after the startup of the compressor, or the
change in the number of operating indoor units is made (including a
change by turning thermo-ON/OFF).
3. After the condition 2 above is satisfied, the thermistor of indoor unit
in STOP detects TH22j
[
−5 [23°F] for 5 consecutive minutes.
Wrong piping connection between indoor unit and
branch box
Miswiring between indoor unit and branch box
Miswiring of LEV in branch box
Malfunction of LEV in branch box
●Diagnosis of defects
Make sure to turn the power OFF before connecting/disconnecting any connectors, or replacing boards.
Diagnosis Remedy
1503
(P6)
Anti-freeze protection of plate heat exchanger
Freeze protection of branch box or indoor unit
No
Yes
No
Yes
No
Yes
Yes
No
60 61
OCH740
Connect the piping and wiring to the same
port.
Is the resistance detected?
Connect the LEV wiring to the intended
port properly.
Disconnect the LEV wiring of branch box
or indoor unit to check the resistance.
Replace the LEV coil.
Check the port which the piping and
wiring between the indoor unit and
branch box is connected.
Is the piping and wiring connected
to the same port?
Check the port which the LEV wiring
of branch box is connected.
Is the wiring connected to the same
port as the corresponding branch
box?
Replace the LEV assy in branch box or
the LEV of indoor unit that is not
via branch box.
Connect the LEV wiring properly.
Check the LEV wiring of indoor
unit that is not via branch box is
connected properly.