116
Control unit
message
System characteristics
Cause
Measures
F.58
Control mode without room
influence
Short circuit, room tem-
perature sensor
Check external room temperature
sensor of heating circuit or room
temperature sensor of remote con-
trol unit.
F.59
Burner locked out
Power supply, low voltage Check the power supply.
F.62
Burner in a fault state
High limit safety cut-out
has responded.
Check fill level of the heating sys-
tem. Check circulation pump. Ven-
tilate system.
Reset device.
F.63
Burner in a fault state
Flue gas temperature lim-
iter has responded.
Check fill level of the heating sys-
tem. Ventilate system.
Unlock the appliance once the flue
system has cooled down.
F.67
Burner in a fault state
Ionisation current lies out-
side the permissible range
Check gas supply (gas pressure
and gas flow switch), gas train and
connection line.
Check ionisation electrode:
■
Distance to burner gauze assem-
bly (see page 79)
■
Contamination of electrode
Reset device.
F.68
Burner in a fault state
Flame signal is already
present at burner start.
Check ionisation electrode and
connecting cable.
Reset device.
F.69
Burner in a fault state
Ionisation current lies out-
side the permissible range
Check ionisation electrode and
connecting cable.
Reset device.
F.70
Burner in a fault state
Internal burner control unit
fault
Reset device.
F.71
Burner in a fault state
Fan speed too low
Check fan on blockade.
Reset device.
F.72
Burner in a fault state
Fan idle state not reached Check draught in flue system.
Check fan.
Check connection cables on fan.
Check fan control.
Reset device.
F.73
Burner in a fault state
Internal communication
error
Check CAN bus connection and
cables.
Reset device.
F.74
Burner blocked.
Internal circulation pump off.
No central heating and no
DHW heating.
System pressure too low
Top up with water.
F.77
Burner in a fault state
Data memory burner con-
trol unit
Check software version. Flash new
version if necessary.
Reset device.
F.89
No central heating and no
DHW heating.
Internal pump blocked
Check pump and replace if neces-
sary.
F.91
Affected extension functions
in emergency mode.
DIO electronics module
communication error
Check connections on DIO elec-
tronics module and connection to
heat management unit.
Troubleshooting
Fault messages on the gas condensing…
(cont.)
5853335
Diagnosis