Mitsubishi Electric MXZ-8A140VA Technical & Service Manual page 44

Error Code Abnormal point and detection method
Indoor–branch box/branch box–outdoor
unit connector miswiring, excessive
number of units
1. Outdoor/branch box controller circuit
board can automatically check the num-
ber of connected indoor units. Abnormal
if the number cannot be checked auto-
matically due to miswiring of indoor–
branch box/branch box–outdoor unit
connecting wire and etc. after power is
turned on for 4 minutes.
EA
(6844)
Miswiring of indoor–branch box/branch
box–outdoor unit
connecting wire (converse wiring or
disconnection)
Outdoor/branch box controller circuit board
can automatically set the unit number of
indoor units.
Abnormal if the indoor unit number can
not be set within 4 minutes after power on
because of miswiring (converse wiring or
Eb
disconnection) of indoor–branch
(6845)
box/branch box–outdoor unit connecting
wire.
Start-up time over
The unit cannot finish start-up process
within 4 minutes after power on.
EC
(6846)
Case
1 Contact failure or miswiring of
indoor/outdoor unit connecting
wire
2 Diameter or length of indoor–
branch box/branch box–out-
door unit connecting wire is out
of specified capacity.
There are 9 or more indoor
units in the system.
There are 3 or more branch
boxes in the system.
3 Defective transmitting receiving
circuit of outdoor/branch box
controller circuit board
4 Defective transmitting receiving
circuit of branch box/indoor
controller board
5 Defective branch box/indoor
power board
6 Noise has entered into power
supply or indoor–branch box
/branch box–outdoor unit
connecting wire.
1 Contact failure or miswiring of
indoor–branch box/branch box
–outdoor unit connecting wire
2 Diameter or length of indoor–
branch box/branch box–out-
door unit connecting wire is out
of specified capacity.
4 Defective transmitting receiving
circuit of outdoor/branch box
controller circuit board
5 Defective transmitting receiving
circuit of indoor/branch box
controller board
6 Defective indoor/branch box
power board
7 Noise has entered into power
supply or indoor–branch
box/branch box–outdoor unit
connecting wire.
1 Contact failure of indoor–
branch box/branch box–out-
door unit connecting wire
2 Diameter or length of indoor–
branch box/branch box–out-
door unit connecting wire is
out of specified capacity.
3 Noise has entered into power
supply or indoor–branch
box/branch box–outdoor unit
connecting wire.
44
Judgment and action
1 Check disconnection or looseness or polarity
of indoor–branch box/branch box–outdoor
unit connecting wire of indoor and outdoor
units.
2 Check diameter and length of indoor–branch
box/branch box–outdoor unit connecting wire.
Total wiring length: 55m (outdoor–branch box)
(including wiring connecting each branch box
unit and between branch box and outdoor
unit)
Also check if the connection order of flat
cable is S1, S2, S3.
If the error "EA" is detected, check the num-
ber of the indoor units and the branch box in
the system.
3~5 Turn the power off once, and on again to
check.
Replace outdoor controller circuit board,
branch box controller board, indoor con-
troller board or indoor power board if
abnormality occurs again.
6 Check transmission path, and remove the
cause.
w The descriptions above, 1-6, are for EA, Eb
and EC.