Checking The Balanced Flue System For Soundness (Annular Gap Check) - Viessmann VITODENS 300 WB3A Service Instructions Manual

Further details regarding the individual steps
Checking the balanced flue system for soundness (annular
gap check)
A Combustion air aperture
Initial start-up, inspection, maintenance
(cont.)
For balanced flue systems tested
together with the gas fired wall
mounted boiler, some Federal States
(e.g. Northrhein-Westphalia) waive
the requirement for a soundness test
(overpressure test) during commis-
sioning by the flue gas inspector.
For such cases we recommend that
your heating contractor carries out a
simple soundness test during the
initial start-up of your system. For
this, it would be sufficient to check the
CO concentration in the combustion
2
air at the annular gap in the balanced
flue pipe.
The flue pipe is deemed to be sound,
if the CO concentration of the com-
2
bustion air is no higher than 0.2 % or
the O concentration is at least
2
20.6 %.
If actual CO values are higher or O
2
values are lower, carry out a pressure
test on the flue pipe at a static pres-
sure of 200 Pa.
2
17