Key:
1 - Negative signal pressure socket
2 - Positive signal pressure socket
3 - Intake sockets (air A) - (flue gases F)
4 - Fan safety pressure switch
5 - Heating NTC limit and regulation sensor
6 - Overtemperature safety thermostat
7 - Primary heat exchanger
8 - Ignition/detection plugs
9 - Combustion chamber
10 - Burner
11 - Air vent valve
12 - Circulating pump
13 - Gas valve
14 - Motor-operated 3-way valve
15 - System filler cock
16 - Expansion tank
17 - Domestic circuit NTC sensor
18 - 316L stainless steel boiler
19 - Domestic circuit 8 bar safety valve
20 - Boiler drain valve
21 - Flue extraction fan
22 - Sealed chamber
23 - Flue extraction hood
24 - System 3 bar safety valve
25 - System drain cock