3.4
BOILER HYDRAULIC DIAGRAM.
Key:
1 - System filling valve
2 - Gas valve
3 - System expansion vessel
4 - Burner
5 - Primary heat exchanger
6 - Fan
7 - Sealed Chamber
8 - Flue pressure switch
9 - Delivery probe
10 - Safety thermostat
11 - Vent valve
12 - Boiler pump
13 - System draining valve
38
14 - System pressure switch
15 - Three-way valve motorised
16 - By-pass
17 - 3 bar safety valve
G - Gas supply
RU - Storage tank unit return (optional)
MU - Storage tank unit flow (optional)
RR - System filling
R - System return
M - System flow
36