Viessmann VITODENS 222-F Service Instructions Manual page 82

Troubleshooting
Corrective Action
82
(continued)
Vitodens 222-F B2TA 19 and 35 Service
Check fixed high limit
Check the fixed high limit, if the burner control cannot be
reset after a fault shutdown, although the boiler water
temperature is below approximately 167° F (75° C):
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 button R
on the boiler control.
Check fuse
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).
Check fuses in the External Accessories Connection Box
1. Switch OFF the power.
2. Open external accessories connection box and check
fuses F1 and F2 (see wiring diagram).