Viessmann VITODENS 300 Service Instructions Manual page 93

Repairs
(cont.)
&
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.
Checking O-rings:
1. Pull off the electrical plug A.
2. Remove sensor B by pulling it
upwards.
3. Ensure that both O-rings C are
properly inserted into aperture
adaptor retainers D.
4. Insert the sensor with connection
nipples into the gas combination
valve adaptor and push in until it
clicks into place.
5. Reconnect the electrical plug-in
connector on the sensor.
Troubleshooting
93