Viessmann Vitodens 333 Service Instructions Manual page 82

Troubleshooting
Repairs
(cont.)
Check the outlet temperature sensor
Checking 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 the reset button "E".
82
1. Pull the leads off the outlet tem-
perature sensor A.
2. Check the sensor resistance and
compare it with the curve.
3. Replace the sensor in cases of
severe deviation.
Danger
The outlet temperature sen-
sor is immersed in the DHW
(risk of scalding).
Drain the secondary side of
the boiler before replacing
the sensor.