Check Code
Abnormal point and detection method
Judgment and action
Case
24
UF
Compressor overcurrent interruption
(When compressor locked)
Abnormal if overcurrent of DC bus or
compressor is detected within 30 seconds
after compressor starts operating.
1
Decrease of power supply voltage
2
Looseness, disconnection or
converse of compressor wiring
connection
3
Defective compressor
4
Defective outdoor power board
5
Decreased water flow
6
Clogged filter of water pipe
7
Clogged plate heat exchanger
8
Locked water pump
9
Malfunction of water pump
1
Check facility of power supply.
2
Correct the wiring (U
•
V
•
W phase) to
compressor.
Refer to "9-6. TEST POINT DIAGRAM"
(Outdoor power circuit board).
3
Check compressor. Refer to
"9-4. HOW TO
CHECK THE PARTS".
4
Replace outdoor power circuit board.
5
–
9
Check water circuit and repair the defect.
Ud
Overheat protection
Abnormal if outdoor pipe thermistor (TH3)
detects 70
:
or more or condensing
temperature of pressure sensor (63HS)
detects 70
:
or more during compressor
operation.
1
Defective outdoor fan (fan
motor) or short cycle of outdoor
unit during cooling operation
2
Defective outdoor pipe
thermistor (TH3)
3
Defective outdoor controller board
4
Defective pressure sensor
1
Check outdoor unit air passage.
23
Turn the power off and on again to check
the check code. If U4 is displayed, follow the
U4 processing direction.
4
Check pressure by microcomputer.
(Pressure sensor/ 63HS) (SW2: Refer to "9-7.
OUTDOOR UNIT OPERATION MONITOR FUNCTION".)
UH
Current sensor error or input current error
·Abnormal if current sensor detects –1.0 A
to 1.0 A during compressor operation.
(This error is ignored during test run.)
1
Disconnection of compressor wiring
2
Defective circuit of current sensor
on outdoor power circuit board
3
Decrease of power supply voltage
4
Leakage or shortage of refrigerant
1
Correct the wiring (U
•
V
•
W phase) to compressor.
Refer to "9-6. TEST POINT DIAGRAM"
(Outdoor power circuit board).
2
Replace outdoor power circuit board.
3
Check the facility of power supply.
4
Check leakage of refrigerant.
UP
Compressor overcurrent interruption
Abnormal if overcurrent DC bus or
compressor is detected after compressor
starts operating for 30 seconds.
1
Decrease of power supply voltage
2
Looseness, disconnection or
converse of compressor wiring
connection
3
Defective fan of outdoor units
4
Short cycle of indoor/outdoor units
5
Defective input circuit of
outdoor controller board
6
Defective compressor
7
Decreased water flow
8
Clogged filter of water pipe
9
Clogged plate heat exchanger
0
Locked water pump
1
Malfunction of water pump
1
Check facility of power supply.
2
Correct the wiring (U
•
V
•
W phase) to
compressor. Refer to "9-6. TEST POINT
DIAGRAM" (Outdoor power circuit board).
3
Check outdoor fan.
4
Solve short cycle.
5
Replace outdoor controller circuit board.
6
Check compressor. Refer to "9-4. HOW TO
CHECK THE PARTS".
Note: Before the replacement of the outdoor
controller circuit board, disconnect the
wiring to compressor from the outdoor
power circuit board and check the output
voltage among phases, U, V, W, during test
run. No defect on board if voltage among
phases (U-V, V-W and W-U) is same. Make
sure to perform the voltage check with
same performing frequency.
7
–
1
Check
water circuit and repair the defect.
E0
or
E4
Remote controller transmission error
(E0)/signal receiving error (E4)
Abnormal if main or sub remote controller
cannot receive any transmission
normally from Interface unit/Flow temp.
controller of refrigerant address “0” for 3
minutes.
(Check code: E0)
Abnormal if sub-remote controller could
not receive any signal for 2 minutes.
(Check code: E0)
Abnormal if Interface/Flow temp.
controller board cannot receive any data
normally from remote controller board or
from other Interface/Flow temp. controller
board for 3 minutes. (Check code: E4)
Interface/Flow temp. controller board
cannot receive any signal from remote
controller for 2 minutes. (Check code:
E4)
Check disconnection or looseness of
Interface unit/Flow temp. controller unit or
transmission wire of remote controller.
Set one of the remote controllers “main”, If
there is no problem with the action above.
Check wiring of remote controller.
Refer to the indoor unit's Installation Manual
for remote controller connection.
If the cause of trouble is not in above – ,
Diagnose remote controllers.
a) When “RC OK” is displayed, remote
controllers have no problem.
Turn the power off, and on again to check.
If abnormality generates again, replace
Interface/Flow temp. controller board.
b) When “RC NG” is displayed, replace
remote controller.
c) When “RC E3” or “ERC 00-66” is displayed,
noise may be causing abnormality.
Contact failure at transmission
wire of remote controller
All remote controllers are set
as “sub” remote controller.
In this case, E0 is displayed
on remote controller, and E4
is displayed at LED (LED1,
LED2) on the outdoor controller
circuit board.
Miswiring of remote controller
Defective transmitting receiving
circuit of remote controller
Noise has entered into the
transmission wire of remote
controller.
E1
or
E2
Remote controller control board
Abnormal if data cannot be read nor-
mally from the nonvolatile memory of the
remote controller control board.
(Check code: E1)
Abnormal if the clock function of remote
controller cannot be operated normally.
(Check code: E2)
Defective remote controller
Replace remote controller.
OCH465D
