Viessmann B2TF - Page 90

90
Displayed fault
code
System characteristics Cause Measures
F.425 System in control mode, cal-
culation out of operation
Time synchronisation
failed
Set the time. If external time is
used, check parameters 1504 and
508.
F.430 Control mode operation in
line with set values of heat
generator
Communication error,
gateway
Check gateway module connecting
cable and power supply.
F.446 Burner in a fault state Deviation, heat generator
flow temperature sensor/
high limit safety cut-out
Check the flow temperature sen-
sor/high limit safety cut-out.
Check plug-in connection and lead
to sensor.
Reset the appliance.
F.447, F.448 Burner in a fault state Deviation, ionisation volt-
age signal
Replace BCU burner control unit:
See page 100.
Reset the appliance.
F.449, F.450,
F.451, F.452
Burner in a fault state Error in scheduled pro-
gram run monitoring
Reset the appliance. If fault recurs,
replace BCU burner control unit:
See page 100.
F.453 Burner in a fault state Synchronisation error, se-
quence
Reset the appliance. If fault recurs,
replace BCU burner control unit:
See page 100.
F.454 Burner in a fault state Incorrect software version Flash the correct software version
for the BCU burner control unit.
F.455 Burner in a fault state Error in program run moni-
toring
Reset the appliance. If fault recurs,
replace BCU burner control unit:
See page 100.
F.456 Burner in a fault state Error in program run moni-
toring
Reset the appliance. If fault recurs,
replace BCU burner control unit:
See page 100.
F.457 Burner in a fault state Fan sluggish or blocked. Reset the appliance.
Check fan for sluggishness. In the
case of severe contamination or
grinding noises, replace fan unit.
Troubleshooting
Fault messages (cont.)
6151778
Service