Modulating Gas Valve; Function; Nomenclature Of The Parts; Adjustment - Biasi Riva Plus HE M296.24SM/C Service Manual

11

ModulATiNG GAS vAlvE

11.1 function

The Modulating 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 Modulating gas valve can be
opened or closed.
By means of an electric command given to the modulation opera-
tor the pressure can be varied and therefore the gas flow rate to
the burner (modulation). The modulation operator has mechani-
cal components which allow the adjustment of the minimum and
maximum pressure exiting the valve.

11.2 Nomenclature of the parts

- (figure 11.2)
1 Minimum gas pressure adjustment
2 Maximum gas pressure adjustment
3 Modulation operator's electric connectors
4 On-off operators electric connector
5 On-off operators
6 Gas valve inlet pressure test point
7 Gas valve outlet pressure test point
8 Modulation operator
ModulATiNG GAS vAlvE
figure 11.2

11.3 Adjustment

for the pressure values refer to the Technical data section
of the user manual and installation instructions.
1 Remove the case panels and the sealed chamber lid (section
2 Open the gas valve inlet pressure test point (6 in Figure 11.2)
3 Remove the gauge and close the pressure test point 6.
4 Open the gas valve outlet pressure test point (7 in Figure
figure 11.3
7
8
6 4
Warning: isolate the boiler from the mains electrici-
ty supply before removing any covering or compo-
nent.
"Body panels" page 5).
at the valve input, connect a suitable pressure gauge and
check the gas pressure of the supply network.
11.2) and connect the gauge;
C
3
2
1
5
b
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