Viessmann B2TF Installation And Service Instructions Manual page 94

Troubleshooting
Fault messages
(cont.)
Displayed fault System characteristics
code
F.540 Burner in a fault state
F.544 Mixer closes. Heating circuit
pump is operational.
F.545 Mixer closes. Heating circuit
pump is operational.
F.546 Mixer closes. Heating circuit
pump is operational.
F.547 Mixer closes. Heating circuit
pump is operational.
94
Cause
Condensate backup in the
heat cell
Lead break, flow tempera-
ture sensor, heating circuit
2 with mixer
Incorrect setting during
commissioning
Short circuit, flow temper-
ature sensor for heating
circuit 2 with mixer
Lead break, flow tempera-
ture sensor, heating circuit
3 with mixer
Short circuit, flow temper-
ature sensor for heating
circuit 3 with mixer
Measures
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.
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.
Check flow temperature sensor,
mixer 2.
Measure voltage at sensor input on
electronics module. Set value:
3.3 V with sensor disconnected
–
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.
Check flow temperature sensor,
mixer 3.
Measure voltage at sensor input on
electronics module. Set value:
3.3 V with sensor disconnected
–