Viessmann B0KA Installation And Service Instructions Manual page 58

Troubleshooting
Fault messages
(cont.)
Displayed fault System characteristics
code
7 No DHW heating
8 No DHW heating
13 Regulates as if the outside
temperature were 0 °C.
14 Regulates as if the outside
temperature were 0 °C.
49 Burner in a fault state
50 Burner in a fault state
57 Normal operation without
room influence
58 Normal operation without
room influence
59 Burner blocked, boiler circuit
pump off. No central heating,
no DHW heating
58
Cause
Lead break, cylinder tem-
perature sensor
Short circuit, cylinder tem-
perature sensor
Lead break, outside tem-
perature sensor
Short circuit, outside tem-
perature sensor
Lead break, flue gas tem-
perature sensor
Short circuit, flue gas tem-
perature sensor
Lead break, room temper-
ature sensor
Short circuit, room tem-
perature sensor
Power supply, low voltage
Measures
Check DHW setting in the com-
■
missioning assistant and correct
if required.
Check the cylinder temperature
■
sensor (terminal 2).
Measure voltage at sensor input
■
on HBMU heat management
unit. Set value: 3.3 V with sen-
–
sor disconnected
Replace faulty component if re-
quired.
Check the cylinder temperature
sensor (terminal 2).
Replace faulty component if re-
quired.
Check operating mode setting in
■
commissioning assistant and
remedy if required.
Check outside temperature sen-
■
sor and connection to sensor
(terminal 4).
Measure voltage at sensor input
■
on HBMU heat management
unit. Set value: 3.3 V with sen-
–
sor disconnected
Replace faulty component if re-
quired.
Check outside temperature sensor
and connection to sensor (terminal
4). Replace faulty components if
necessary.
Check flue gas temperature sen-
sor.
Reset the appliance.
Check flue gas temperature sen-
sor.
Reset the appliance.
Check commissioning setting of
■
remote control.
Check plug and cable of external
■
room temperature sensor, heat-
ing circuit.
If no external room temperature
■
sensor installed, replace Vitotrol
programming unit.
Check plug and cable of external
room temperature sensor, heating
circuit.
If no external room temperature
sensor installed, replace Vitotrol
programming unit.
Check mains voltage.
If voltage is correct and the fault
occurs repeatedly, replace the fan
unit.