Service manual

Service manual E000129004
10
2.9. C.h. pressure relief valve
F Removal
Warning: isolate the boiler from the mains
electricity supply before removing any covering or
component.
1 Remove the cover (section 1.4).
2 Empty the main circuit (section 1.5)
3 Lower the control panel (section 1.7)
4 By means of a suitable spanner unscrew and remove
the valve A (Fig. 28).
5 Re-assemble the sensor following the removal
procedures in the reverse order.
Fig. 28
2.10. Electronic control p.c.b.
The fundamental function of the electronic control
p.c.b. is that of controlling the boiler in relation to the
external needs (i.e. heating the dwelling or heating the
water for d.h.w. use) and operating in order to keep the
room temperature and the domestic hot water to the
desired value.
This is obviously possible within the useful power and
maximum working temperature limits foreseen.
The electronic control p.c.b. does also a sequence of
operations (ignition cycle) which lead to the ignition of
the gas at the burner and checks the presence of the
flame during the entire period in which it is activated
Generally, the electronic control p.c.b. receives inlet in-
formation coming from the boiler (the sensors) or from
the outside (user settings, room thermostat, etc.), pro-
cesses it and consequently acts with outlet commands on
other components of the boiler.
F Removal
Warning: isolate the boiler from the mains
electricity supply before removing any covering or
component.
1 Remove the cover (section 1.4).
2 Lower the control panel (section 1.7)
3 Disconnect all the wirings connected to the p.c.b.
4 Unscrew the screws A (Fig. 29) and remove the
electronic control p.c.b.
5 Re-assemble the electronic control p.c.b. carrying out
the removal operations in reverse order.
Fig. 29
2.11. Display p.c.b.
F Removal
Warning: isolate the boiler from the mains
electricity supply before removing any covering or
component.
1 Remove the cover (section 1.4).
2 Lower and open the control panel (section 1.7).
3 Remove the electronic control p.c.b. as explained in the
section 2.10
4 Unscrew the screws A (Fig. 30) and remove the display
p.c.b.
5 Re-assemble the display p.c.b. carrying out the removal
operations in reverse order.
Fig. 30