79
Note
For diagnosis and troubleshooting, see chapter
"Repairs".
Fault messages dependent on appliance equipment
level
Displayed fault
code
System characteristics
Cause
Measures
F.5
Flow rate not being moni-
tored. System continues op-
erating in normal mode with
replacement value.
Lead break or short cir-
cuit, flow sensor
Check plug 33/X6 and cable be-
tween BCU burner control unit and
flow sensor:
■
Check voltage level, to see if 5 V
present at plug 33, pin 1 and 2.
■
Turn the gas condensing boiler
ON/OFF switch off and back on
again.
F.7
No DHW heating
Lead break, cylinder tem-
perature sensor
■
Check DHW setting in the com-
missioning assistant and correct
if required.
■
Check cylinder temperature sen-
sor (plug 5, wires 3 and 4).
■
Measure voltage at sensor input
on electronics module. Set value:
3.3 V
–
with sensor disconnected.
Replace faulty component if re-
quired.
F.8
No DHW heating
Short circuit, cylinder tem-
perature sensor
Check cylinder temperature sensor
(plug 5, wires 3 and 4).
Replace faulty component if re-
quired.
F.11
No solar DHW heating or
central heating backup
Lead break, collector tem-
perature sensor
■
Check collector temperature sen-
sor.
■
Measure voltage at sensor input
on electronics module. Set value:
3.3 V
–
with sensor disconnected
F.12
No solar DHW heating
Short circuit, collector
temperature sensor
■
Check collector temperature sen-
sor.
■
Measure voltage at sensor input
on electronics module. Set value:
3.3 V
–
with sensor disconnected
F.13
Regulates as if the outside
temperature were 0 °C.
Lead break, outside tem-
perature sensor
■
Check operating mode setting in
commissioning assistant and
remedy if required.
■
Check outside temperature sen-
sor and connection to sensor
(external plug, contacts 1 and 2).
■
Measure voltage at sensor input
on electronics module. Set value:
3.3 V
–
with sensor disconnected.
Replace faulty component if re-
quired.
F.14
Regulates as if the outside
temperature were 0 °C.
Short circuit, outside tem-
perature sensor
Check outside temperature sensor
and connection to sensor (external
plug, and contacts 1 and 2). Re-
place faulty components if neces-
sary.
Troubleshooting
Fault messages
6151778
Service
