Viessmann VITODENS 050-W Installation And Service Instructions Manual page 52

Troubleshooting
Fault display
Fault code System character-
displayed istics
51 No DHW heating
52 Burner blocked
59 No DHW heating
5A Burner blocked
A9 Control mode with-
out OpenTherm in-
fluence
b0 Burner blocked
b8 Burner blocked
E3 Burner in a fault
state
E5 Burner blocked
F0 Burner blocked
F1 Burner in a fault
state
F2 Burner in a fault
state
52
(cont.)
Cause
Short circuit, outlet
temperature sen-
sor
Short circuit, flow
sensor
Lead break, outlet
temperature sen-
sor
Lead break, flow
sensor
Communication
error, OpenTherm
device
Short circuit, flue
gas temperature
sensor
Lead break, flue
gas temperature
sensor
Fault in safety
chain
Internal fault
Internal fault
Max. flue gas tem-
perature exceeded
Temperature limit-
er has responded.
Measures
Check the sensor (see
page 60).
Check connections and
lead; replace sensor if re-
quired.
Check the sensor (see
page 60).
Check connections and
leads. Replace sensor if
required.
Check connections and
leads. Replace Open-
Therm device if necessa-
ry.
Check the sensor (see
page 61).
Check the sensor (see
page 61).
Check the temperature
limiter and connecting
leads (see page 59).
Check the ionisation
electrode and connecting
cables.
Replace control unit.
Check heating system fill
level. Check circulation
pump. Vent the system.
Check heating system fill
level. Check circulation
pump. Vent the system.
Check the temperature
limiter and connecting
leads (see page 59).
Press "Reset" (see
page 54).