27
OCH748
Check Code Abnormal point and detection method
Cause
Judgment and action
P6
(1503)
Freezing/overheating protection is working
(1) Freezing protection
Plate HEX Liquid temperature (TH34)
or refrigerant saturation temperature is
10 seconds smaller than the threshold.
The threshold is dynamically calculated
by inner operation using the operating
time of the compressor and the water
temperature.
(1) Freezing protection
<Cooling mode>
1
Reduced water flow
· Clogged filter
· Leakage of water
2
Low temperature
· Low-load
· Inlet water is too cold.
3
Defective water pump
4
Defective outdoor fan control
5
Leakage or shortage of refrigerant
6
Defective refrigerant circuit (clogs)
7
Malfunction of linear expansion valve
<Heating mode>
1
Reduced water flow
· Clogged filter
· Leakage of water
2
Low temperature
· Low-load
· Inlet water is cold.
3
Defective water pump
4
Leakage or shortage of refrigerant
5
Malfunction of linear expan-
sion valve
(1) Freezing protection
<Cooling mode>
12
Check water piping.
3
Check water pump.
4
Check outdoor fan motor.
5
–
7
Check operating condition of refrigerant
circuit.
7
Check linear expansion valve.
<Heating mode>
12
Check water piping.
3
Check water pump.
4
Correct to proper amount of refrigerant.
5
Check linear expansion valve. Refer to "9-6.
HOW TO CHECK THE COMPONENTS".
P8
(1110)
Pipe temperature
Abnormal if the following conditions are
detected for continuously 3 minutes after
compressor starts operating for 10 minutes.
1. Cooling mode
TH6
−
TH7
[
2°C and
TH3−TH7
[
4°C
or TH6−TH3 < 0
°C and
THW2 (Indoor)−TH34
[
0°C
2. Heating mode
T63HS−THW2 (Indoor)
[
2°C and
TH6−THW2 (Indoor)
[
1°C and
TH7−TH3
[
1°C
T63HS: Condensing temperature of pres-
sure sensor (63HS)
Thermistor
TH3: Liquid temperature
TH34: Plate HEX Liquid temperature
TH7: Ambient temperature
THW2(Indoor): Return water temp from
indoor unit thermistor
1
Leakage or shortage of
refrigerant
2
Malfunction of linear expansion
valve
3
Refrigerant circuit is clogged
with foreign objects.
Note: Clogging occurs in the
parts which become below
freezing point when water
enters in refrigerant circuit.
4
Disconnection of thermistor
holder
1
Check intake superheat.
Check leakage of refrigerant.
2
Check linear expansion valve.
3
After recovering refrigerant, remove water
from entire refrigerant circuit under vacuum
more than 1 hour.
4
Check temperature display on outdoor
controller circuit board.
Temperature display is indicated by setting
SW2 of outdoor controller circuit board.
Check the holder of thermistor.
UE
(1509)
Abnormal pressure of pressure sensor
(63HS)
Abnormal if pressure sensor (63HS)
detects 0.1 MPa or less.
Detection is inoperative for 3 minutes after
compressor starting and 3 minutes after
and during defrosting.
1
Disconnection or contact fail-
ure of connector (63HS) on
the outdoor controller circuit
board
2
Defective pressure sensor
3
Defective outdoor controller
circuit board
1
Check connection of connector (63HS) on
the outdoor controller circuit board.
Check breaking of the lead wire for thermis-
tor (63HS).
2
Check pressure by microprocessor. (Pressure
sensor/ 63HS) (SW2: Refer to "9-8.
OUTDOOR UNIT OPERATION MONITOR
FUNCTION".)
3
Replace outdoor controller board.
PE
Inlet water temperature
Abnormal if the following conditions are
detected for continuously 10 seconds.
1. Cooling mode
During compressor operation
THW2 (Indoor) < 3°C
2. Heating mode (exclude defrosting)
During compressor operation
THW2 (Indoor) < −10
°C
3. Defrosting mode
During compressor operation
THW2 (Indoor) < 0°C
Thermistor
THW2 (Indoor): Return water temp from
Indoor unit thermistor
1
Reduced water flow
· Clogged filter
· Leak of water
2
Low temperature
· Low-load
· Low temperature inlet water
3
Defective water pump
4
Leakage or shortage of refrig-
erant
12
Check water piping.
3
Check water pump.
4
Check intake superheat.
Check leakage of refrigerant.
