Mitsubishi Electric PUHZ-FRP71VHA2 Service Manual page 27

Check Code Abnormal points and detection method
Miswiring of indoor/outdoor unit
connecting wire
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.
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)
OCH665B
Cause
1 Contact failure or miswiring of
indoor/outdoor unit connecting
wire
2 Diameter or length of indoor/
outdoor unit connecting wire is
out of specified capacity.
3 Excessive number of indoor
units are connected to 1
outdoor unit. (4 units or more)
4 Defective transmitting receiving
circuit of outdoor controller
circuit board
5 Defective transmitting receiving
circuit of indoor controller board
6 Defective indoor power board
7 Noise has entered into power
supply or indoor/outdoor unit
connecting wire.
1 Contact failure or miswiring of
indoor/outdoor unit connecting
wire
2 Diameter or length of indoor/
outdoor unit connecting wire is
out of specified capacity.
3 Defective transmitting receiving
circuit of outdoor controller circuit
board
4 Defective transmitting receiving
circuit of indoor controller board
5 Defective indoor power board
6 Noise has entered into power
supply or indoor/outdoor unit
connecting wire.
1 Contact failure of indoor/
outdoor unit connecting wire
2 Diameter or length of indoor/
outdoor unit connecting wire is
out of specified capacity.
3 Noise has entered into power
supply or indoor/outdoor unit
connecting wire.
27
Judgment and action
1 Check disconnection or looseness or polarity
of indoor/outdoor unit connecting wire of
indoor and outdoor units.
2 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.
3 Check the number of indoor units that are
connected to one outdoor unit. (If EA is
detected)
4–6 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.
7 Check transmission path, and remove the
cause.
Note: The descriptions above, 1–7, are for EA,
Eb and EC.