Viessmann Vitodens 333-F Service Instructions Manual page 91

Repairs
(cont.)
Checking the outlet temperature sensor
Check the flue gas temperature sensor
The flue gas temperature sensor locks out the boiler when the permissible flue
gas temperature is exceeded. Reset the interlock after the flue gas system has
cooled down by pressing "E RESET".
1. Pull the leads from outlet tempera-
ture sensor A.
2. Check the sensor resistance and
compare it with the curve.
3. Replace the sensor in case of
severe deviation.
Danger
The outlet temperature sen-
sor is immersed in the DHW
(risk of scalding).
Drain the DHW side of the
boiler before replacing the
sensor.
Troubleshooting
91