1. With the boiler operating in the maximum rate condition check that the
operational (working) gas pressure at the inlet gas pressure test point
is in accordance with BS 6798 & BS 6891. This must be AT LEAST
18mb !
2. Ensure that this inlet pressure can be obtained with all other gas
appliances in the property working. The pressure should be measured
at the gas test point on the gas inlet (A).
3. Measure the gas rate— With any other appliances & pilot lights turned
OFF the gas rate can be measured. It should be:-
Tab.21 Natural gas
15 model
1.64 m
3
/h
18 model
1.96 m
3
/h
7.4.2
Checking combustion - chimney sweep mode
The case front panel must be fitted when checking combustion.
Ensure the system is cold and the gas and electric supplies are turned
on.
Important
The person carrying out a combustion measurement should have
been assessed as competent in the use of a flue gas analyser and
the interpretation of the results.
1
Combustion test point
2
Incoming air for combustion test point
Important
Allow the combustion to stabilise before inserting the Combustion
Analyser Probe into the Test Point (1). This will prevent saturation
of the analyser.
The combustion must be measured and recorded at the Maximum and
Minimum heat inputs.
Fig.37
Gas inlet test point
A
PN-0000362
Fig.38
Flue adaptor test points
PN-0000363
1
2
7 Commissioning
43
