Viessmann Vitodens 333 Service Instructions Manual page 89

Repairs
(cont.)
Check the temperature limiter
Checking and replacing pressure differential sensor
Check the sensor in case of fault messages concerning the differential pressure
sensor:
&
correct installation
&
electrical connection
&
correct position of the O-rings inside the adaptor
&
are the test nipples closed with plugs?
Replace the sensor if fault messages persist.
If the burner control unit cannot be
reset after a fault shutdown, although
the boiler water temperature is below
approx. 75 °C:
&
Pull the leads from temperature lim-
iter A.
&
Check the continuity of the tempera-
ture limiter with a multimeter.
&
Remove faulty temperature limiter.
&
Install a new temperature limiter.
&
After commissioning, press reset
button E on the control unit.
Troubleshooting
89