Benchmark Alpha E-Tec Plus 28 Installation And Servicing Instruction page 11

3.8 BOILER SCHEMATIC
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1 Gas isolation valve
2 Cold mains isolation valve with
integrated filling valve
3 Gas valve
4 DHW flow switch
5 Gas injector
6 Flow regulator
7 DHW temperature sensor
8 Condensate trap
9 3 bar safety valve
10 Expansion vessel
Domestic
hot water
outlet
Gas
Cold mains
water inlet
Condensate discharge
11 Venturi positive pressure point (+)
and expansion relief
12 Venturi
13 Primary flow temperature sensor
14 Ignition/sensing electrode
15 Air supply pipe
16 Flue temperature sensor
17 Flue test point (pressure point +)
18 Air test point (pressure point -)
19 Burner
20 Primary return sensor
21 Fan
Primary
Heating
return
Primary
Heating flow
Fig. 3.5
Alpha E-Tec Plus 28, 33 and 38 - Technical Data
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22 Automatic air vent
23 Boiler pump
24 Primary pressure switch
25 DHW heat exchanger
26 Diverter valve
27 By-pass
28 Drain point
29 Safety valve indicator
30 Filling loop
31 Heating return isolation valve
with integrated filling valve
32 Heating flow isolation valve
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