7
2.7 BOILER SCHEMATIC
Fig. 2
1 - Heat exchanger thermal fuse
2 - Gas valve
3 - Primary temperature sensor
4 - Main burner
5 - Primary/condensing heat exchanger
6 - Manual air vent
7 - Fan
8 - Pressure differential test points
9 - Flue hood
10 - Overheat thermostat
11 - Expansion vessel
12 - Automatic air vent
13 - Pump
14 - Drain point
15 - Pressure relief valve
16 - Primary pressure switch
17 - Ignition electrodes
18 - Flame sensing electrode
19 - Flue sampling point
20 - Gas service cock
21 - On/off valve (2 off)
22 - Automatic by-pass
23 - Cyclone separator (if applicable)
24 - Condensate trap
25 - Injector
26 - Venturi
27 - Venturi positive point
28 - Venturi negative point
29 - Flue temperature sensor
Gas
Condensate
discharge
Primary
Heating
return
Primary
Heating flow
-
+
-
+
20
2
19
6
1
7
24
35
8
29
3
10
17
11
27
28
12
13
14
15
22
23
21
3
16
9
5
4
18
26
25
Alpha InTec S - Technical Data