
24
11
Gas valve
11.1
Function
The Gas valve
A
in Fig. 11.1 controls the gas inflow to
the boiler burner.
A
Fig. 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 (Fig. 11.2)
1
Minimum gas pressure adjustment
2
On---off operators
3
On---off operators electric connector
4
Gas valve inlet pressure test point
2
3
1
4
Fig. 11.2
11.3
Adjustment
Warning: isolate the boiler from the mains
electricity supply before removing any
covering or component.
Check the supply pressure before making any ad-
justment to the gas valve.
1
Close the gas inlet valve.
2
Remove the front panel of the case and lower the
control panel (see sections 2.2 and 2.3).
3
Loosen the internal screw on the Inlet Pressure
Test Point 4 (Fig. 11.2) of the Gas valve and con-
nect a pressure gauge using a suitable hose.
4
Open the gas inlet valve.
5
Turn on the electricity supply to the boiler, switch-
ing on the fused spur isolation switch.
The appliance operation light on the left will flash
every 4 seconds.
6
Set the function knobs as illustrated in Fig. 11.4.
7
Open at least one hot water tap fully.
8
Read the inlet pressure value and ensure that it is
within the 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.
9
Switch off the boiler
close the gas inlet valve
and
close the water tap
.
10
Disconnect the pressure gauge and close the
Inlet Pressure Test Point 4 (Fig. 11.2).
Gas valve adjustment
11
Fit the probe of the flue analyser in the flue ex-
haust sampling point located on the exhaust
pipes of the boiler (Fig. 11.3)
air---flue exhaust
sampling points
Fig. 11.3
12
Turn on the boiler, switching on the fused spur
isolation switch.
13
Open the gas inlet valve.
14
Set the function knob
B
as indicated in Fig. 11.4.
The appliance operation light on the left will flash
every 4 seconds.
C
E
D
B
F
Fig. 11.4