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11 GAS VALVE
11 .1 Function
The gas valve "A" in Figure 11.1 controls the gas inflow to the
boiler burner.
A
Figure 11 .1
By means of an electric command given to the on-off operators
the passage of the gas through the Gas valve can be opened or
closed.
11 .2 Description of the parts
(Figure 11 .2)
B Maximum boiler power adjustment
C Minimum boiler power adjustment
D On-off operators
E On-off operators electric connector
F Gas valve inlet pressure test point
F
Figure 11 .2
- 30 -
GAS VALVE
11 .3 Adjustment
Check the supply pressure before making any adjustment
to the gas valve .
1 Close the gas inlet valve.
2 Remove the front panel of the case and lower the control
3 Loosen the internal screw on the Inlet Pressure Test Point "F"
4 Open the gas inlet valve.
5 Turn on the electricity supply to the boiler, switching on the
6 Set the boiler in C.H. / D.H.W. function as illustrated in Figure
Figure 11 .3
7 Open at least one hot water tap fully.
8 Read the inlet pressure value and ensure that it is within the
9 Switch off the boiler close the gas inlet valve and close the
10 Disconnect the pressure gauge and close the Inlet Pressure
Gas valve adjustment
B
C
11 Fit the probe of the flue analyser in the flue exhaust sampling
D
E
Figure 11 .4
12 Turn on the boiler, switching on the fused spur isolation
Warning: isolate the boiler from the mains electrici-
ty supply before removing any covering or compo-
nent .
panel (see sections "2.2 Case panels" on page 5 and "2.3
Control panel" on page 6).
(Figure 11.2) of the Gas valve and connect a pressure gauge
using a suitable hose.
fused spur isolation switch.
11.3.
limits given in the table Gas supply pressures, of the user/
installation manual. If it does not comply with the required
pressure check the gas supply line and governor for faults
and/or correct adjustment.
water tap.
Test Point "F" (Figure 11.2).
The person carrying out a combustion measure-
ment should have been assessed as competent in
the use of a flue gas analyser and the interpretation
of the results. The flue gas analyser used should be
one meeting the requirements of BS7927 or BS-
EN50379-3 and be calibrated in accordance with the
analyser manufacturers' requirements, and have a
current calibration certificate.
point located on the exhaust pipes of the boiler (Figure 11.4).
air intake
sampling point
switch.
C.H. / D.H.W.
function
flue
exhaust
sampling point
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