Viessmann WB1A007 Installation And Service Instructions Manual page 66

Troubleshooting
Correction
(continued)
A
66
Check fixed high limit
If the burner control unit cannot be reset after a fault shutdown (F2), even
though the boiler water temperature is below approx. 203°F / 95°C, check the
fixed high limit.
1. Pull the leads from fixed high limit
.
2. Check the continuity of the fixed
high limit with a multimeter.
3. Remove faulty fixed high limit.
4. Coat the replacement fixed high limit
with heat conducting paste and
install.
5. To reset press "Reset" on the
control unit.