14
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
L
EGEND
:
1.
Fan
2.
Main heat exchanger
3.
Overheat thermostat
4.
Burner
5.
Ignition electrodes
6.
Detection electrode
7.
Regulation thermostat
8.
Frost thermostat
9.
Gas valve
10. Pump pressure switch
11. Safety valve (3 bar)
12. Boiler drain valve
13. Automatic by-pass
14. Pressure gauge
15. Circulation pump with automatic
air release valve
16. Expansion vessel
17. Air pressure switch
A. Central Heating Flow
B. Inlet Gas
C. Central Heating Return
2.12
G
AS AND
W
ATER
C
IRCUITS
F
IG
. 2.14
F
IG
. 2.13