Viessmann Vitoladens 300-C Installation And Service Instructions Manual page 40

Commissioning, inspection, maintenance
Cleaning the heating surfaces
Biferral heating surface and stainless steel heat exchanger
Fig. 35
40
(cont.)
1. Use a vacuum cleaner to remove deposits from the
heating surfaces (angled nozzle available as
accessory).
2. Pull the condensate hose from the neutralising sys-
tem.
3. Flush the stainless steel heat exchanger with
water.