Alpha CD12S - Boiler Schematic

6
2.11 BOILER SCHEMATIC
Fig. 2
Alpha CD12S/20S/28S - Technical Data
1 - Flue sampling point
2 - Flue temperature sensor
3 - Injector
4 - Gas valve
5 - Primary temperature sensor
6 - Venturi
7 - Main burner
8 - Primary/condensing heat exchanger
9 - Room sealed chamber
10 - Fan
11 - Pressure differential test points
12 - Flue hood
13 - Overheat thermostat
14 - Expansion vessel
15 - Automatic air vent
16 - Pump
17 - Drain point
18 - Pressure relief valve
19 - Primary pressure switch
20 - Ignition electrodes
21 - Flame sensing electrode
22 - Venturi negative point
23 - Venturi positive point
24 - Gas service cock
25 - On/off valve (2 off)
26 - Automatic by-pass
27 - Cyclone separator (if applicable)
28 - Condensate trap
29 - Heat exchanger thermal fuse
Gas
Condensate
discharge
Primary
Heating
return
Primary
Heating
flow
24
4
1
-
-
+
+
9
10
28
11
2
13
5
20
14
22
23
15
19
16
17
18
26
27
25
12
8
7
21
6
3
29