43
Check code
Title and display conditions
Possible Cause
Diagnosis and action
L8
Heating operation error
Note: “3” is displayed in “Request code: 567” in
“Running information”.
<Heating/FS>
If a), b) and c) occur, L8 is displayed;
a) No change on THW1 and THW5B
(under 1°C for 20 minutes from unit starts
operation)
b) No change on THW1
(under 1°C for 10 minutes from booster heater
starts operation)
c)
THW1−THW2 < −5°C
(for 10 minutes continuously)
1. THW1 has become detached from its
holder.
1. Visually inspect location and reattach as
necessary.
2. Booster heater fault
2. Electrically test to determine fault.
See "Checking Component Parts' Function"
3. THW1 or THW2 or 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.
Heating operation error
Note: “A” is displayed in “Request code: 567” in
“Running information”.
1. THW6 has become detached from its
holder.
1. Visually inspect location and reattach as
necessary.
2. THW6 or THW7 fault
2. Check resistance of thermistor against table
in "Checking Component Parts' Function".
Compare FTC detected temperature to
hand held detector.
3. FTC board failure
3. Replace board.
Heating operation error
Note: “C” is displayed in “Request code: 567” in
“Running information”.
1. THW8 has become detached from its
holder.
1. Visually inspect location and reattach as
necessary.
2. THW8 or THW9 fault
2. Check resistance of thermistor against table
in "Checking Component Parts' Function".
Compare FTC detected temperature to
hand held detector.
3. FTC board failure
3. Replace board.
L9
Note: “1” is displayed in “Request code: 569” in
“Running information”.
<DHW/Heating/LP/FS>
Exception
For 1 minute after water circulation pump1 is
switched on.
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 air.
Check the strainer for blockages.
Check the primary water circuit for leaks.
recommended range.
3. Valve 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. Connector/terminal wire has become
detached or loose wiring.
5. Visually check the CN1A connector and IN2
terminal and reattach if necessary.
6. Flow sensor fault
6. Electrically test to determine fault.
See "Checking Component Parts Function"
for how to check.
7. Incorrect setting of the SW2-2
7. Check the SW2-2 setting.
8. FTC board failure
8. Replace board.
Note: “2” is displayed in “Request code: 569” in
“Running information”.
1.
1. If more head required either add a pump of
the same size or replace existing 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 air.
Check the strainer for blockages.
Check the primary water circuit for leaks.
recommended range.
3. Terminal wire has become detached or
loose wiring.
3. Visually check the IN3 terminal and reattach
if necessary.
4. Flow switch fault
4. Electrically test to determine fault
5. Incorrect setting of the SW3-2
5. Check the SW3-2 setting.
6. FTC board failure
6. Replace board.
