Viessmann B1HF - Page 81

81
Displayed fault
code
System characteristics Cause Measures
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.
544 Emergency function operat-
ing mode is activated for
heating circuit 2:
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 setting in the commission-
ing assistant and correct if re-
quired.
Checking setting of ADIO rotary
switch.
545 Emergency function operat-
ing mode is activated for
heating circuit 2:
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
574 Room temperature sensor for
heating circuit 1 not available
Normal operation without
room influence
Check external room temperature
sensor in heating circuit or room
temperature sensor on remote
control unit
738 Normal operation OpenTherm remote con-
trol unit connected but not
configured
Set C.7 in the commissioning as-
sistant to a value of 14.
Troubleshooting
Fault messages (cont.)
6167586
Diagnosis