87
Fault number
on the display
System characteristics
Cause
Measures
F.468
Burner in a fault state
Ionisation current too high
during calibration
Check gap between ionisation
electrode and burner gauze as-
sembly.
Heat generator installation
and service instructions
Check whether there is a lot of
dust in the ventilation air (e.g. from
construction work).
Note
Deposits on the electrodes indicate
foreign bodies in the ventilation air.
Check the installation room and
flue system for causes of the de-
posits. For example: Laundry de-
tergents, cleaning agents, toilet-
ries, deposits in the ventilation air
supply (chimney).
If burner gauze assembly and ioni-
sation electrode have been re-
placed, also clean fan unit, gas/air
channel and Venturi extension.
Reset the appliance.
F.471
No heat demand
System pressure sensor
not available
Check the system pressure sensor.
F.473
No heat demand
HMU heat management
unit communication error
Check connecting cable between
burner control unit and HMU heat
management unit.
F.474
Burner in a fault state
Error in scheduled pro-
gram run monitoring
Reset the appliance.
F.517
Control mode, remote control
unit not functioning
Communication error
wired remote control
Vitotrol
Check remote control unit connect-
ing cable and setting.
F.527
Burner locked out
Update parameters faulty
or incomplete
Repeat BCU burner control unit
flash operation.
F.528
Burner locked out
Basic programming faulty
or incomplete
Repeat BCU burner control unit
flash operation.
F.540
Burner in a fault state
Condensate backup in the
heat cell
Check system for condensate
backup.
Check the condensate drain and
trap.
Note
To prevent water damage, detach
fan unit before removing the burn-
er.
Reset the appliance.
F.542
Mixer closes. Heating circuit
pump is operational.
Lead break, flow tempera-
ture sensor, heating circuit
1 with mixer
Check flow temperature sensor
TS1 on extension kit mixer (ADIO
electronics module). See
page 91.
Troubleshooting
Fault messages
(cont.)
6130884
Service
