Viessmann Vitodens 333 Service Instructions Manual page 83

Repairs
(cont.)
Checking the plate-type heat exchanger
Drain the primary and secondary side
of the boiler.
During removal, small amounts of
water may trickle out and escape from
the removed plate-type heat exchan-
ger.
1. Pull the leads off the flue gas tem-
perature sensor A.
2. Check the sensor resistance and
compare it with the curve.
3. Replace the sensor in cases of
severe deviation.
Troubleshooting
83