Mitsubishi Electric PUZ-HA24NHA1, Service Manual

Page: 30 / 128

30
OCH750A
Abnormal point and detection method Judgment and action
Eb
(6845)
Miswiring of indoor/outdoor unit
connecting wire (converse wiring or dis-
connection)
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 con-
necting wire.
EC
(6846)
Startup time over
The unit cannot finish startup process
within 4 minutes after power on.
Cause
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 the 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 the case of group control)
8
Noise has entered into power
supply or indoor/outdoor unit
connecting wire.
1
Check disconnection or looseness or polar-
ity 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 the case of group control
system.
8
Check transmission path, and remove the
cause.
Note: The descriptions above
1
–
8
are for EA,
Eb and EC.
EA
(6844)
F5
(5201)
63H connector open
Abnormal if 63H connector circuit is open
for 3 minutes continuously after power sup-
ply.
63H: High pressure switch
1
Disconnection or contact failure
of 63H connector on outdoor
controller circuit board
2
Disconnection or contact failure
of 63H
3
63H is working due to defective
parts.
4
Defective outdoor controller
circuit board
1
Check connection of 63H connector on
outdoor controller circuit board.
Refer to "10-8. TEST POINT DIAGRAM".
2
Check the 63H side of connecting wire.
3
Check continuity by tester.
Replace the parts if the parts are defective.
4
Replace outdoor controller circuit board.
Check Code
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, etc. after power is
turned on for 4 minutes.
2. Abnormal if outdoor controller circuit
board recognizes excessive number of
indoor units.
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 out-
door 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
2 or more outdoor units have
refrigerant address “0” .
(In the case of group control)
8
Noise has entered into power
supply or indoor / outdoor unit
connecting wire.