94
Displayed fault
code
System characteristics
Cause
Measures
F.540
Burner in a fault state
Condensate backup in the
heat cell
■
Check system for condensate
backup.
■
Check the condensate drain and
trap.
■
Replace insulation blocks, elec-
trodes and burner gauze assem-
bly if required.
Note
To prevent water damage, detach
fan unit before removing the burn-
er.
Reset the appliance.
F.544
Mixer closes. Heating circuit
pump is operational.
Lead break, flow tempera-
ture sensor, heating circuit
2 with mixer
Incorrect setting during
commissioning
Check flow temperature sensor,
mixer 2.
Measure voltage at sensor input on
electronics module. Set value:
3.3 V
–
with sensor disconnected.
Check commissioning assistant
setting.
Checking setting of ADIO rotary
switch.
F.545
Mixer closes. Heating circuit
pump is operational.
Short circuit, flow temper-
ature sensor for heating
circuit 2 with mixer
Check flow temperature sensor,
mixer 2.
Measure voltage at sensor input on
electronics module. Set value:
3.3 V
–
with sensor disconnected
F.546
Mixer closes. Heating circuit
pump is operational.
Lead break, flow tempera-
ture sensor, heating circuit
3 with mixer
Check flow temperature sensor,
mixer 3.
Measure voltage at sensor input on
electronics module. Set value:
3.3 V
–
with sensor disconnected.
Check commissioning assistant
setting. Checking setting of ADIO
rotary switch.
F.547
Mixer closes. Heating circuit
pump is operational.
Short circuit, flow temper-
ature sensor for heating
circuit 3 with mixer
Check flow temperature sensor,
mixer 3.
Measure voltage at sensor input on
electronics module. Set value:
3.3 V
–
with sensor disconnected
Troubleshooting
Fault messages
(cont.)
6151778
Service