Check Outdoor Temperature Sensor - Viessmann Vitodens 100-W WB1B Series Installation And Service Instructions Manual

Troubleshooting
Boiler Connection

Check outdoor temperature sensor

Temperature
78
(continued)
Vitodens 100-W, WB1B Installation & Service
1. Disconnect cables from outdoor sensor.
2. Measure resistance of the outdoor sensor and
compare with resistance / outdoor sensor curve
shown below.
3. If the value measured differs significantly, replace
the sensor.
In weather-compensated mode (optional), the boiler
water temperature is regulated subject to the outside
temperature.
Frost protection function
Built-in automatic frost protection allows the boiler to be
shut off for an extended period of time while protecting it
against freeze-up. Frost protection is continually active. The
burner is switched ON when the boiler water temperature
reaches 41º F (5º C) and is switched OFF again when the
boiler water temperature reaches at least 59º F (15º C)
[but not more than 68º F (20º C)].
For details on the control, please refer to the
Vitodens 100-W Operating Instructions.