Checking The Balanced Flue System Tightness (Annular Gap Check) - Viessmann FB2A Installation And Service Instructions For Contractors

Commissioning, inspection, maintenance
Further details regarding the individual steps
4. "Change?" Select "Yes".
A value flashes on the display (e.g.
"85"). In the delivered condition, this
value represents 100 % of rated out-
put.
Checking the balanced flue system tightness (annular gap
check)
A Combustion air port (ventilation air)
For balanced flue systems tested
together with the wall mounted gas fired
boiler, the requirement for a tightness
test during commissioning by the flue
gas inspector is not applicable.
34
(cont.)
5. Set the required value.
We recommend that your heating engi-
neer carries out a simple leak/tightness
test during the commissioning of your
system. For this, it would be sufficient to
check the CO or O
2
combustion air at the annular gap of the
balanced flue pipe.
The flue pipe is deemed to be gas-tight
if the CO concentration in the combus-
2
tion air is no higher than 0.2 % or the
O concentration is at least 20.6 %.
2
If actual CO values are higher or O
2
ues are lower, then pressure test the flue
pipe with a static pressure of 200 Pa.
concentration in the
2
val-
2