Installation & Servicing instructions ATAG iC-Range
58
13.2 CO and combustion checks
IMPORTANT PRELIMINARY INFORMATION ON CHECKS
NOTE: The air gas ratio valve is factory set and must not be adjusted during commissioning unless
this action is recommended following contact with the manufacturer.
If any such adjustment is recommended and further checking of the boiler is required the installer/service
engineer must be competent to carry out this work and to use the flue gas analyser accordingly.
If the boiler requires conversion to operate with a different gas family (e.g. conversion from natural gas to
LPG) separate guidance will be provided by the boiler manufacturer
PRIOR TO CO LEVEL AND COMBUSTION RATIO CHECK
The boiler manufacturer’s installation instructions should have been followed, gas type verified and gas
supply pressure/rate checked as required prior to commissioning.
As part of the installation process,
especially where a flue has been fitted by persons other than the
boiler installer
, visually check the integrity of the whole flue system to confirm that all components are
correctly assembled, fixed and supported. Check that manufacturer’s max. flue lengths have not been
exceeded and all guidance has been followed (e.g. Gas Safe Technical Bulletin TB008 where chimney/flues
are in voids).
The Flue Gas Analyser should be of the correct type, as specified by BS 7967
Prior to its use, the flue gas analyser should have been maintained and calibrated as specified by the
manufacturer. The installer must have the relevant competence for use of the analyser.
Check and zero the analyser IN FRESH AIR as per analyser manufacturer’s instructions.
Key:
CO
= carbon monoxide
CO
2
= carbon dioxide
O
2
= oxygen
ppm
= parts per million
Combustion ratio
= The CO reading measured in ppm divided by the CO
2
reading first converted to ppm
GU(I&U)R
= Gas safety (Installation & use) Regulation.
SET BOILER TO MAXIMUM RATE
In accordance with boiler instructions, set
boiler to operate at maximum rate (full load
condition). Allow sufficient time for
combustion to stabilise.
NOTE
- Do not insert analyser probe during
this period to avoid possible “flooding” of sensor.
CARRY OUT FLUE INTEGRITY CHECK USING ANALYSER
Insert analyser probe into air inlet test point and allow readings to
stabilise.
NOTE
- where no air inlet test point is provided then a flue integrity
check with the analyser is not possible. The installer should verify
that flue integrity has been visually checked in accordance with the
yellow
“Prior to CO and combustion ratio check”
box above
before proceeding to the
“Check CO and combustion ratio at
maximum rate”
stage below.
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