Mitsubishi Electric PUZ-WZ50VAA Service Manual page 33

Check code Abnormal points and detection method
Indoor/outdoor unit connector
miswiring, excessive number of units (2
units or more)
1. Outdoor controller circuit board can
automatically check the number of
connected indoor units. Abnormal if the
number cannot be checked automatically
due to miswiring of indoor/outdoor unit
connecting wire and etc. after power is
turned on for 4 minutes.
2. Abnormal if outdoor controller circuit
board recognizes the number of
connected indoor units as "2 units or
EA more".
(6844)
Miswiring of indoor/outdoor unit
connecting wire (reverse wiring or
disconnection)
Outdoor controller circuit board can
automatically set the unit number of indoor
units.
Abnormal if the indoor unit number cannot
be set within 4 minutes after power on
because of miswiring (reverse wiring
Eb
or disconnection) of indoor/outdoor unit
(6845)
connecting wire.
Startup time over
The unit cannot finish startup process within
4 minutes after power on.
EC
(6846)
Incorrect connection
The outdoor unit does not receive the sig-
EE
nals of I/F or FTC.
OCH816
Cause
Contact failure or miswiring of
indoor/outdoor unit connecting wire
Diameter or length of indoor/
outdoor unit connecting wire is
out of specified capacity.
2 or more indoor units are
connected to one outdoor unit.
Defective transmitting receiving
circuit of outdoor controller
circuit board
Defective transmitting receiving
circuit of indoor controller board
Defective indoor power board
Do NOT use refrigerant
address 0, as 0 is used for FTC
(Master). The address range
is 1 to 6. (In case of multiple
outdoor units control.)
Noise has entered into power
supply or indoor/outdoor unit
connecting wire.
Contact failure or miswiring of
indoor/outdoor unit connecting wire
Diameter or length of indoor/
outdoor unit connecting wire is
out of specified capacity.
Defective transmitting receiving
circuit of outdoor controller circuit
board
Defective transmitting receiving
circuit of indoor controller board
Defective indoor power board
Do NOT use refrigerant
address 0, as 0 is used for FTC
(Master). The address range is
1 to 6. (In case of multiple out-
door units control.)
Noise has entered into power
supply or indoor/outdoor unit
connecting wire.
Contact failure of indoor/
outdoor unit connecting wire
Diameter or length of indoor/
outdoor unit connecting wire is
out of specified capacity.
Do NOT use refrigerant
address 0, as 0 is used for FTC
(Master). The address range is
1 to 6. (In case of multiple out-
door units control.)
Noise has entered into power
supply or indoor/outdoor unit
connecting wire.
A device other than Interface
unit or Flow temp. controller
unit is connected to the unit.
33
judgment and action
Check disconnection or looseness or polarity
of indoor/outdoor unit connecting wire of
indoor and outdoor units.
Check diameter and length of indoor/outdoor
unit connecting wire.
Total wiring length: 80 m
(including wiring connecting each indoor unit
and between indoor and outdoor unit)
Also check if the connection order of flat cable
is S1, S2, S3.
Check the number of indoor units that are
connected to one outdoor unit. (If EA is
detected)
– Turn the power off once, and on again to
check.
Replace outdoor controller circuit board,
indoor controller board or indoor power
board if abnormality occurs again.
Check if refrigerant addresses (SW1-3 to
SW1-6 on outdoor controller circuit board) are
overlapping in case of multiple outdoor units
control.
Check transmission path, and remove the
cause.
Note: The descriptions above, 1–8, are for EA,
Eb and EC.
Connect I/F or FTC to the unit.