Mitsubishi Electric PUZ-SM100VKA2 Service Manual page 30

Check code Abnormal points and detection method
Miswiring of indoor/outdoor unit
connecting wire
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 excessive number of
indoor units.
EA
(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
or disconnection) of indoor/outdoor unit
Eb
connecting wire.
(6845)
Startup time over
The unit cannot finish startup process
within 4 minutes after power on.
EC
(6846)
OCH774A
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.
Excessive number of indoor
units are connected to 1 out-
door unit. (4 units or more)
Defective transmitting receiving
circuit of outdoor controller
circuit board
Defective transmitting receiving
circuit of indoor controller board
Defective indoor power board
2 or more outdoor units have
refrigerant address "0" .
(In case of group 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
2 or more outdoor units have
refrigerant address "0" .
(In case of group 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.
2 or more outdoor units have
refrigerant address "0" .
(In case of group control)
Noise has entered into power
supply or indoor/outdoor unit
connecting wire.
30
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/out-
door 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 group control
system.
Check transmission path, and remove the
cause.
The descriptions above, – , are common for
EA, Eb and EC.