Viessmann WB2-44 - Page 31

Troubleshooting
31
Cause of fault Corrective action
Short circuit – outdoor temperature sensor Check outdoor temperature sensor (see page 40).
Open circuit – outdoor temperature sensor Check outdoor temperature sensor (see page 40).
Short circuit – low-loss header temperature sensor Check supply temperature sensor (see page 40).
Open circuit – low-loss header temperature sensor Check supply temperature sensor (see page 40).
Short circuit – boiler temperature sensor Check boiler temperature sensor (see page 40).
Open circuit – boiler temperature sensor Check boiler temperature sensor (see page 40).
Short circuit – supply temperature sensor See Installation Instructions Mix. Valve Actuator.
See coding address “000” (see page 49).
See coding address “0B8” (see page 56).
Open circuit – supply temperature sensor See Installation Instructions Mix. Valve Actuator.
See coding address “000” (see page 49).
See coding address “0B8” (see page 56).
Short circuit – tank temperature sensor Check tank temperature sensor (see page 41).
See coding address “000” (see page 49).
See coding address “0B8” (see page 56).
Open circuit – tank temperature sensor Check tank temperature sensor (see page 41).
See coding address “000” (see page 49).
See coding address “0B8” (see page 56).
Internal BUS f ault Replace VR20 (see page 61).
Replace LGM 29 (see page 62).
Replace entire control console.
5285 961 v1.3