Viessmann VITODENS 200-W WB2B Series Start-Up/Service Instructions page 62

Troubleshooting
Corrective Action
A
Fig. 23
A
Fig. 24
62
(continued)
Check fixed high limit
Check the fixed high limit, if the burner control cannot be reset after a fault
shutdown, although the boiler water temp. is below approx. 75°C / 167°F:
1. Remove cables from the fixed high
limit A.
2. Check the continuity of the fixed
high limit with a multimeter.
3. Remove and replace a defective
fixed high limit.
4. After starting up the boiler, press "
RESET" on the boiler control.
Check fuse
F1
Check fuses in the power/pump module
1. Switch OFF the power.
2. Release side latches and
pivot the control unit down.
3. Remove cover A.
4. Check fuse F1 (see wiring diagram).
1. Switch OFF the power.
2. Open power/pump module and
check fuses F1 and F2
(see wiring diagram).