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5 Remove the protection cap B (Figure 11.3) from the me-
chanical pressure adjustment components levering with a flat
screwdriver in the slots C.
6 Start the boiler at its maximum power.
Operate the boiler in d.h.w. mode or ensure that the boiler is
not range rated if the test is carried out in c.h. mode.
7 Rotate the maximum gas pressure adjustment (2 in Figure
11.2) until you obtain the required pressure (by rotating clock-
wise the pressure increases).
8 Turn the boiler off and disconnect one of the two connectors
(3 in Figure 11.2).
9 Start the boiler and rotate the minimum gas pressure adjust-
ment (1 in Figure 11.2) until you obtain the required pressure
(by rotating clockwise the pressure increases).
10 Turn the boiler off and re-connect the wire to the modulating
operator.
11 Start the boiler and check again the maximum gas pressure
setting.
12 Turn the boiler off and disconnect the gauge.
Important: after the gas pressure checks and any adjust-
ment operations, all of the test points must be sealed and
replace the adjustment protection cap .
11 .4 Checks
Warning: isolate the boiler from the mains electrici-
ty supply before removing any covering or compo-
nent .
Check the modulation operator coil
1 Remove the front panel of the case.
2 Disconnect the connectors D (Figure 11.5) from the modulat-
ing operator and measure the electrical resistance of the coil.
Its electrical resistance value must be approx. 80 Ω*.
Check the on-off operators coils
1 Remove the front panel of the case.
2 Disconnect the electrical connector E (Figure 11.5).
3 Measure the electrical resistance between the connector pins
of the on-off operators as illustrated in Figure 11.4.
Upper on-off operator
approx. 6400 *
Lower on-off operator
approx. 920 *
*at ambient temperature.
Figure 11 .4
11 .5 Removal of the on-off operators coils
Warning: isolate the boiler from the mains electrici-
ty supply before removing any covering or compo-
nent .
1 Remove the front panel of the case.
2 Disconnect the connector E (Figure 11.5).
3 Unscrew the screw F and remove on-off operator coils.
4 Reassemble the coils carrying out the removal operations in
reverse order.
MODULATING GAS VALVE
Figure 11 .5
11 .6 Removal of the gas valve
1 Remove the front panel of the case as explained in the sec-
2 Disconnect the connectors D and E (Figure 11.5).
3 Turn off the gas supply and disconnect the gas isolation cock
4 Unscrew the connectors G and remove the pipe H.
5 Remove the rubber pipe I.
6 Unscrew the screws J and remove the valve.
7 Reassemble the valve carrying out the removal operations in
After any service operation on the components of the gas
circuit check all the connections for gas leaks .
G
I
E
J
Warning: isolate the boiler from the mains electrici-
ty supply before removing any covering or compo-
nent .
tion "Control panel" page 5 of this manual.
connector from the inlet port of the gas valve.
reverse order.
Warning: After cleaning or replacement as detailed
above, if it deemed necessary to undertake a com-
bustion analysis, refer to the appropriate chapter
Maintenance of the installation instructions manual .
H
D
F
- 29 -
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