Viessmann Vitodens 100-W B1HA 26 Installation And Service Instructions Manual page 68

Troubleshooting
Boiler Connection
Start-up and Maintenance
68
Vitodens 100-W, B1HA/B1KA 26 to 125 Combi Installation/Service
(continued)
Check Control unit fuse
1. Switch off main power supply.
2. Flip down control unit.
3. Remove cover A.
4. Check fuse F4 T 2.5A (slow blow).
Replacements fuses are available from Viessmann.
Check DHW outlet temperature sensor (B1KA only)
1. Pull the leads from outlet temperature sensor A.
2. Check the sensor resistance and compare it with
the curve.
3. Replace the sensor in case of severe deviation.
Note: Water can leak when replacing the outlet
temperature sensor. Shut off the cold water
supply. Drain the DHW line and the plate type
heat exchanger (DHW side).
Temperature
Check DHW tank temperature sensor (B1HA only)
%
1. Remove plugs from the cable harness.
2. Check the sensor resistance and compare it with
the curve.
3. Replace the sensor in case of severe deviation.