Viessmann VITODENS 343-F WS4A Installation And Service Instructions Manual page 108

Troubleshooting
Repairs
(cont.)
If the burner control unit cannot be
reset after a fault shutdown, although
the boiler water temperature is below
approx. 75 °C, check the following:
1. Pull the leads from
thermocouple A.
2. Check the continuity of the thermo-
couple with a multimeter.
Checking the fuse in the wiring chamber
1. Switch OFF the power.
2. Remove the cover from the wiring
chamber.
108
3. Remove the faulty thermocouple.
4. Install a new thermocouple.
5. After commissioning, press reset
button "E RESET" at the control
unit.
3. Check fuse F1.