SERVICE AND SPARES
6 720 644 743a (2010/10)
44
6.2 CHECK THE GAS INLET PRESSURE
Refer to section 5.5.1 for more information
B Check the gas supply working pressures in the system
conform to the readings shown in the table below:
6.3 CHECKING FLUE INTEGRITY
The integrity of the flue system and performance of the
boiler can be checked via the flue turret sample points.
Fig. 68 Flue test points
B With the boiler case on and the boiler running at
maximum.
B Insert the analyser probe into the air intake test point.
B Allow the readings to stabilise and check that:
– O
2
is equal to, or greater than 20.6%
– CO
2
is less than 0.2%
B If the readings are outside these limits then this
indicates that there is a problem with the flue system
or combustion circuit.
Fig. 69 Flue integrity test
NOTICE:
B Ensure that the gas inlet pressure is
satisfactory with all other gas appliances
working.
B Do not continue with the other checks if
the correct gas inlet pressure can not be
achieved.
Natural gas
Allowed mbar pressure drop
meter/
regulator
across
pipework
boiler
inlet
across
boiler
gas control
valve
19 - 23 1 18-22 1.5 16.5 - 20.5
L.P.G.
32 - 45 2.5 29.5 - 42.5 1.5 28 - 41
mbar range
Flue gas sample point 1
Air inlet sample point 2
Tab. 23 Key to figure 68
2
1
2
2
1
1
6720643895-67.1Wo
6720643895-104.1Wo
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