41
Self-diagnosis and action
Check if DIP SW is set correctly. (Refer to "DIP switch functions".)
Check code
Title and display conditions
Possible Cause
Diagnosis and action
L3
Circulation water temperature overheat
protection
<DHW/Heating/Cooling/LP/FS/OS>
Check code displayed when THW1 detects a
temp. ≥ 80ºC for 10 consecutive seconds or
THW2 detects a temp. ≥ 80ºC for 10 consecutive
seconds.
DHW: Domestic hot water mode
Heating: Heating mode
Cooling: Cooling mode
LP:
Legionella p
revention mode
FS:
Freeze stat
OS:
Operation stop
TH1A/B: Room temp. thermistor
TH2:
Liquid refrigerant temp. thermistor
THW1: Flow water temp. thermistor
THW2: Return water temp. thermistor
THW5B: DHW tank lower water temp. thermistor
THW6:
THW7: Zone1 return water temperature thermistor
THW8:
THW9: Zone2 return water temperature thermistor
THWB1: Boiler flow water temperature thermistor
1.
1 Refer to table in "Checking Component
Parts' Function" to determine if system
pump meets requirements.
If more head required either add a pump of
the same size or replace existing pump with
capacity model.
See "DISASSEMBLY PROCEDURE" for
how to replace pump.
2.
Due to 1 or more of the following;
blocked strainer, leak in water circuit.
2. Check circulation pump (See "Checking
Component Parts' Function" for how to
check).
Open purge valve to remove trapped ai
r.
Check the strainer for blockages.
Check the primary water circuit for leaks.
recommended range.
3. V
alve operation fault
3.
Check valves on primary water circuit are
installed level.
4.
2-way valve (local
supply) actuator fault 4. Electrically test to determine fault
5.
3-way valve actuator fault
5. 1) Electrically test to determine fault.
2)
Operate 3-way valve manually using
the main remote controller. (Refer to
<Manual operation> in "9-5. Service
menu".)
3) Replace 3-way valve coil.
4)
Replace 3-way valve. (Refer to Procedure
6 in “11. DISASSEMBLY PROCEDURE.”
6. Booster heater relay (BHC1, BHC2,
BHCP) operating fault
6. Electrically test the relays (BHC1, BHC2,
BHCP) to determine fault.
See "Checking Component Parts'
Function" for how to check.
7.
Power supply voltage increase
7.
Check the supply voltage.
8.
THW1 or THW5 has become detached
from its holder.
8.
Visually inspect location and reattach as
necessary.
9. THW1 or THW2 fault
9. Check resistance of thermistor against table
in "Checking Component Parts' Function”
Compare FTC detected temperature to
hand held detector.
10.
FTC board failure
10.
Replace board.
L4
Tank water temperature overheat protection
<DHW/Heating/Cooling/LP/FS/OS>
Check code display when THW5B detects a
temp. ≥ 75ºC for 10 consecutive seconds.
1.
3-way valve actuator fault
1. 1) Electrically test to determine fault.
2)
Operate 3-way valve manually using
the main remote controller. (Refer to
<Manual operation> in "Service
menu".)
3) Replace 3-way valve coil.
4)
Replace 3-way valve. (Refer to Procedure
6 in “DISASSEMBLY PROCEDURE.”
2. Immersion heater relay (IHC) operating
fault
2. Check immersion heater relay (IHC).
3. THW5B fault
3. Check resistance of thermistor against table
in "Checking Component Parts' Function”
Compare FTC detected temperature to
hand held detector.
4. FTC board failure
4. Replace board.
