21
<Abnormalities detected while unit is operating>
Check code
Abnormal point and detection method
Judgment and action
U1
High pressure (High-pressure switch
63H activated)
Abnormal if high-pressure switch 63H is
activated (*) during compressor operation.
*4.15 MPa
63H: High-pressure switch
1
Decreased water flow
2
Clogged filter of water pipe
3
Dirt of plate heat exchanger
4
Locked water pump
5
Malfunction of water pump
6
Clogged or broken pipe
7
Locked outdoor fan motor
8
Malfunction of outdoor fan
motor
9
Short cycle of outdoor unit
0
Dirt of outdoor heat exchanger
1
Decreased airflow caused by
defective inspection of outside
temperature thermistor
(It detects lower temperature
than actual temperature.)
2
Disconnection or contact failure
of connector (63H) on outdoor
controller board
3
Disconnection or contact failure
of 63H connection
4
Defective outdoor controller
board
5
Defective operation of linear
expansion valve
6
Malfunction of fan driving circuit
1
–
5
Check water circuit and repair the defect.
6
Check piping and repair the defect.
7
–
0
Check outdoor unit and repair the defect.
1
Check the detected temperature of outside
temperature thermistor on LED display.
(SW2: Refer to "9-7. OUTDOOR UNIT
OPERATION MONITOR FUNCTION".)
2
–
4
Turn the power off and check F5 is
displayed when the power is turned on
again.
When F5 is displayed, refer to “Judgment
and action” for F5.
5
Check linear expansion valve.
Refer to "9-5. HOW TO CHECK THE
COMPONENTS".
6
Replace outdoor controller board.
Case
U2
High discharge temperature
Abnormal if discharge temperature
thermistor (TH4) exceeds 125
:
or 110
:
continuously for 5 minutes.
Abnormal if during defrosting discharge
temperature thermistor (TH4) exceeds
110
:
continuously for 30 minutes.
High comp. surface temperature
Abnormal if comp. surface temperature
(TH33) exceeds 125
:
.
In the case of high comp. surface
temperature error, compressor does
not restart unless the thermistor (TH33)
becomes less than 95
:
.
1
Overheated compressor
operation caused by insufficient
refrigerant
2
Defective thermistor
3
Defective outdoor controller
board
4
Defective operation of linear
expansion valve
5
In the case of the unit does not
restart :
Detection temp. of thermistor
(TH33)
]
95
:
1
Check intake super heat.
Check leakage of refrigerant.
Charge additional refrigerant.
23
Turn the power off and check if U3 is
displayed when the power is turned ON
again.
When U3 is displayed, refer to “Judgment
and action” for U3.
4
Check linear expansion valve.
Refer to "9-5. HOW TO CHECK THE
COMPONENTS".
U3
Open/short circuit of discharge
temperature thermistor (TH4)/comp.
surface thermistor (TH33)
Abnormal if open (3
:
or less) or short
(217
:
or more) is detected during
compressor operation.
(Open (3
:
or less) detection is inoperative
for 10 minutes of compressor starting
process and for 10 minutes after or during
defrosting.)
1
Disconnection or contact failure
of connector (TH4/TH33) on
the outdoor controller circuit
board.
2
Defective thermistor
3
Defective outdoor controller
circuit board
1
Check connection of connector (TH4/TH33) on
the outdoor controller circuit board.
Check the lead wire for thermistor (TH4/TH33).
Refer to "9-6. TEST POINT DIAGRAM".
2
Check resistance value of thermistor (TH4/
TH33) or temperature on LED display.
(Thermistor/TH4/TH33: Refer to "9-5. HOW
TO CHECK THE COMPONENTS".)
(SW2: Refer to "9-7. OUTDOOR UNIT
OPERATION MONITOR FUNCTION".)
3
Replace outdoor controller board.
OCH465D
