Mitsubishi Electric Mr.SLIM PU-P71VHA Service Manual page 38

Error Code Meaning of error code and detection method
Indoor/outdoor unit connector mis-
wiring, excessive number of units (5
units or more)
1. Outdoor controller board can
automatically check the number of
connected indoor units. Abnormal if the
number of connected indoor units can
not be set within 4 minutes after power
on because of mis-wiring of indoor/
outdoor unit connecting wire and the like.
2. Abnormal if outdoor controller board
EA
recognizes excessive number of indoor
(6844)
unit.
Miswiring of indoor/outdoor unit
connecting wire (converse wiring or
disconnection)
Outdoor controller 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 disconnection) of indoor/outdoor unit
connecting wire.
Eb
(6845)
Start-up time over
The unit can not finish start-up process
within 4 minutes after power on.
EC
(6846)
Serial communication error
The communication between outdoor
controller board and M-NET P.C. board is
not available.
Ed
(0403)
OC379F
Case
1 Contact failure or mis-wiring 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. (5 units or more)
4 Defective transmitting receiving
circuit of outdoor controller
board
5 Defective transmitting receiving
circuit of indoor controller
board
6 Noise has entered into power
supply or indoor/outdoor unit
connecting wire.
7 Remote controller is wired up
among indoor units (twin, triple
or quadruplet units).
8 Two or more outdoor units has
refrigerant address "0."
(In case of group control).
1 Contact failure or mis-wiring of
indoor/outdoor unit connecting
wire
2 Diameter or length of indoor/
outdoor unit connecting wire is
out of specified capacity.
4 Defective transmitting receiving
circuit of outdoor controller board
5 Defective transmitting receiving
circuit of indoor controller board
6 Noise has entered into power
supply or indoor/outdoor unit
connecting wire.
7 Remote controller is wired up
among indoor units (twin, triple
or quadruplet units).
8 Two or more outdoor units has
refrigerant address "0."
(In case of group control).
9 Outdoor power supply board is
defective.
1 Contact failure of indoor/
outdoor unit connecting wire
2 Diameter or length of indoor/
outdoor unit connecting wire is
out of specified capacity.
6 Noise has entered into power
supply or indoor/outdoor unit
connecting wire.
7 Remote controller is wired up
among indoor units (twin, triple
or quadruplet units).
8 Two or more outdoor units has
refrigerant address "0."
(In case of group control).
1 Breaking of wire or contact
failure of connector between
outdoor controller board and
M-NET P.C. board.
2 Contact failure of M-NET P.C.
board power supply line
3 Entrance of noise into
transmission wire
4 Defective transmitting receiving
circuit of M-NET P.C. board
5 Defective serial transmitting
receiving circuit of outdoor
controller board
38
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.
Outdoor-indoor units' interval: 50m maximum
Indoor-indoor units' interval: 30m maximum
Also check if the connection order of flat
cable (VVF etc.) is S1, S2, S3.
3 Check the number of indoor units that are
connected to one outdoor unit. (If EA is
detected.)
45 Turn the power off, and on again to check.
Replace outdoor controller board or indoor
controller board if abnormality is displayed
again.
Check the indoor/ outdoor unit connecting
wire.
6 Inspect transmission line to solve the problem.
7 Wire the remote controller to one of the
multiple indoor units.
8 Set the refrigerant address of outdoor units
with different number starting from "0."
9 Unless the wire has contact failure,
disconnect CN2S on indoor power supply
board to measure the voltage. When CN2S
does not have a current of DC12V to DC16V,
replace the indoor power supply board.
The descriptions above, 1-9, are for EA, Eb
and EC.
1 Check disconnection, looseness, or breaking
of connecting wire between outdoor
controller board CN1 and M-NET P.C. board
CN5.
2 Check departure or looseness of M-NET P.C.
board power supply line (CND-TB1).
3 Replace M-NET P.C. board.
4 Replace outdoor controller board.