16
<Abnormalities detected while unit is operating>
Error 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 (
w
) during compressor opera-
tion.
w
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 8-
8-7.)
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 8-5.
6
Replace outdoor controller board.
Case
U2
High discharging 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 tem-
perature 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 dis-
played when the power is turned ON again.
When U3 is displayed, refer to “Judgement
and action” for U3.
4
Check linear expansion valve.
Refer to 8-5.
U3
Open/short circuit of discharge
temperature thermistor (TH4)/comp. sur-
face thermistor (TH33)
Abnormal if open (3
:
or less) or short
(217
:
or more) is detected during
compressor operation.
(Open (3
:
or less) detection is inopera-
tive 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 8-6.
2
Check resistance value of thermistor (TH4/
TH33) or temperature on LED display.
(Thermistor/TH4/TH33: Refer to 8-5.)
(SW2: Refer to 8-7.)
3
Replace outdoor controller board.
