17
Checking the balanced flue system tightness (annular gap
check)
A
Combustion air aperture
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.
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
2
or O
2
concentration in the
combustion air at the annular gap of the
balanced flue pipe.
The flue pipe is deemed to be gas-tight
if the CO
2
concentration in the combus-
tion air is no higher than 0.2 % or the
O
2
concentration is at least 20.6 %.
If actual CO
2
values are higher or O
2
val-
ues are lower, then pressure test the flue
pipe with a static pressure of 200 Pa.
Commissioning, inspection, maintenance
Further details regarding the individual steps
(cont.)
5692 860 GB
Summary of Contents for CU3A
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