Mitsubishi Electric PUHZ-SW75VHA Service Manual page 23

Error Code Abnormal point and detection method
2 connector open (SW100/120 only)
Abnormal if both 63H and 63L connector
circuits are open for three minutes
continuously after power supply.
63H: High-pressure switch
F9
63L: Low-pressure switch
Indoor/outdoor unit connector
miswiring, excessive number of units (4
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
EA
board recognizes the number of
connected indoor units as "4 units or
more".
Miswiring of indoor/outdoor unit
connecting wire (converse wiring or
disconnection)
Outdoor 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 disconnection) of indoor/outdoor unit
Eb
connecting wire.
Start-up time over
The unit cannot finish start-up process
within 4 minutes after power on.
EC
Incorrect connection
The outdoor unit does not receive the sig-
nals of I/F or FTC.
EE
OCH533A
Case
1 Disconnection or contact failure
of connector (63H,63L) on
outdoor controller circuit board.
2 Disconnection or contact failure
of 63H, 63L
3 63H and 63L are working due
to defective parts.
4 Defective outdoor controller
board.
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 4 or more indoor units are
connected to one outdoor unit.
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 2 or more outdoor units have
refrigerant address "0" .
(In case of group control)
8 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.
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 2 or more outdoor units have
refrigerant address "0" .
(In case of group control)
8 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.
7 2 or more outdoor units have
refrigerant address "0" .
(In case of group control)
8 Noise has entered into power
supply or indoor/outdoor unit
connecting wire.
1 A device other than Interface
unit or Flow temp. controller
unit is connected to the unit.
23
Judgment and action
1 Check connection of connector (63H,63L) on
outdoor controller circuit board.
Refer to 10-7.
2 Check the 63H and 63L side of connecting
wire.
3 Check continuity by tester.
Replace the parts if the parts are defective.
4 Replace outdoor controller circuit board.
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: 80m
(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 if refrigerant addresses (SW1-3 to
SW1-6 on outdoor controller circuit board) are
overlapping in case of group control system.
8 Check transmission path, and remove the
cause.
* The descriptions above, 1-8, are for EA, Eb
and EC.
1 Connect I/F or FTC to the unit.