20
Check Code
Abnormal points and detection method
Judgment and action
U1
(1302)
High pressure (High-pressure switch
63H operated)
Abnormal if high-pressure switch 63H
(4.15MPa) operated during compressor
operation.
1
Decreased water flow
2
Clogged filter of water pipe
3
Locked water pump
4
Malfunction of water pump
5
Dirt of indoor heat exchanger
6
Defective operation of stop
valve (Not full open)
7
Clogged or broken pipe
8
Locked outdoor fan motor
9
Malfunction of outdoor fan motor
0
Short cycle of outdoor unit
1
Dirt of outdoor heat exchanger
2
Decreased airflow caused by
defective inspection of outside
temperature thermistor
(It detects lower temperature
than actual temperature.)
3
Disconnection or contact failure
of connector (63H) on outdoor
controller board
4
Disconnection or contact failure
of 63H connection
5
Defective outdoor controller board
6
Defective action of linear
expansion valve
7
Malfunction of fan driving circuit
1
−
5
Check water circuit and repair defect.
6
Check if stop valve is fully open.
7
Check piping and repair defect.
8
−
1
Check outdoor unit and repair defect.
2
Check the detected temperature of outside
temperature thermistor on LED display.
(SW2 on A-Control Service Tool : Refer
to
"10-7. FUNCTION OF SWITCHES,
CONNECTORS AND JUMPERS".)
3
−
5
Turn the power off and check if F5 is
displayed when the power is turned on
again.
When F5 is displayed, refer to “Judgment
and action” for F5.
6
Check linear expansion valve.
Refer to "10-4. HOW TO CHECK THE PARTS".
7
Replace outdoor controller board.
Case
U2
(TH32:1132)
High comp. surface temperature
(1) Abnormal if comp. surface thermistor (TH32)
exceeds 125°C
or 115°C continuously for
5 minutes.
Abnormal if comp. surface thermistor (TH32)
exceeds 110°C or more continuously for
30 seconds after 90 seconds have passed
since the defrosting operation started.
(2) Abnormal if discharge superheat
(Cooling: TH32−T
63HS
Heating: TH32−T
63HS
) increases.
All the conditions in A or B are detected
simultaneously for 10 minutes continu
-
ously after 6 minutes past from compres
-
sor start-up (including the thermostat
indication or recovery from defrosting).
<Condition A>
• Heating mode
• When discharge superheat is less than
70°C
.
• When the TH6 temp is more than the
value obtained by TH7−5
:
.
• When the condensing temp of TH5 is
less than 35
:
.
<Condition B>
• During compressor operation (Cooling
and Heating)
• When discharge superheat is less than
80
°C
in Cooling.
• When discharge superheat is less than
90°C
in Heating.
• When condensing temp of TH6 is
more than −40
:
. (In Cooling only.)
1
Overheated compressor
operation caused by shortage
of refrigerant
2
Defective operation of stop
valve
3
Defective thermistor
4
Defective outdoor controller
board
5
Defective action of linear
expansion valve
1
Check intake superheat.
Check leakage of refrigerant.
Charge additional refrigerant.
2
Check if stop valve is fully open.
34
Turn the power off and check if U3 is
displayed when the power is on again.
When U3 is displayed, refer to “Judgement
and action” for U3.
5
Check linear expansion valve.
Refer to "10-4. HOW TO CHECK THE
PARTS".
<Abnormalities detected while unit is operating>
U3
(TH32:5132)
Open/short circuit of comp. surface
thermistor (TH32)
Abnormal if open (−20
°C
or less) or
short (217
°C
or more) is detected during
compressor operation.
(Detection is inoperative for 10 minutes
of compressor starting process and for 10
minutes after and during defrosting.)
1
Disconnection or contact failure
of connector (TH32) on the
outdoor controller circuit board
2
Defective thermistor
3
Defective outdoor controller
circuit board
1
Check connection of connector (TH32) on the
outdoor controller circuit board.Check breaking
of the lead wire for thermistor TH32). Refer to
"10-6. TEST POINT DIAGRAM".
2
Check resistance value of thermistor (TH32)
or temperature by microprocessor.(Thermistor/
TH32: Refer to "10-4. HOW TO CHECK THE
PARTS".)(SW2 on A-Control Service Tool:
Refer to "10-7. FUNCTION OF SWITCHES,
CONNECTORS AND JUMPERS".)
3
Replace outdoor controller board.
OCH583
