73
Displayed fault
code
System characteristics
Cause
Measures
575
Normal operation without
room influence
Lead break, room temper-
ature sensor, heating cir-
cuit 1
Check external room temperature
sensor for heating circuit or room
temperature sensor on remote
control unit.
576
Normal operation without
room influence
Short circuit, room tem-
perature sensor, heating
circuit 1
Check external room temperature
sensor for heating circuit or room
temperature sensor on remote
control unit.
577
Normal operation without
room influence
Room temperature sen-
sor, heating circuit 2 not
available
Check external room temperature
sensor for heating circuit or room
temperature sensor on remote
control unit.
Check setting of parameter 934.6
578
Normal operation without
room influence
Lead break, room temper-
ature sensor, heating cir-
cuit 2
Check external room temperature
sensor for heating circuit or room
temperature sensor on remote
control unit.
579
Normal operation without
room influence
Short circuit, room tem-
perature sensor, heating
circuit 2
Check external room temperature
sensor for heating circuit or room
temperature sensor on remote
control unit.
682
Burner in a fault state
Air mass flow rate sensor
not available
Check air mass flow rate sensor.
683
Burner in a fault state
Air mass flow rate sensor
faulty
Check air mass flow rate sensor.
684
Burner in a fault state
Back draught safety de-
vice faulty
Check back draught safety device.
694
Burner in a fault state
Signal comparison, devia-
tion, flue gas high limit
safety cut-out
Check plug-in connection and sen-
sor lead.
Check sensor.
Replace sensor if necessary.
Reset the appliance.
738
Normal operation
OpenTherm remote con-
trol connected but not
configured
Set C.7 in the commissioning as-
sistant to a value of 14.
766
Burner output is reduced to
minimum
Flue gas temperature too
high.
Clean the heat cell. Perform main-
tenance.
767
Burner in a fault state
Flue gas temperature too
high.
Clean the heat cell. Perform main-
tenance.
799
No DHW heating, no central
heating
Central heating circuit
pump reports an electrical
fault. System cannot be
operated as no flow can
be made available.
Perform a power reset. If this oc-
curs repeatedly, replace the heat-
ing circuit pump.
979
Constant heat demand. Set
room temperature is excee-
ded
Both inputs – plug 96
and
OpenTherm – are occu-
pied and reporting a heat
demand
Note
Only one input can be used. Either
plug 96 or OpenTherm.
Troubleshooting
Fault messages
(cont.)
6179762
Diagnosis