
11
1 9 Water circuit
RI
GAS
SC
SF
AA
1
MI
AA
AA
2
3
4
8
9
6
5
7
12
10
14
11
13
13
1
Fan
2
Automatic bleed valve
3
Burner
4
Heat exchanger
5
Drain cock
6
Differential water and minimum pressure switch
7
Circulator (or 2-way valve)
8
Gas valve
9
Flue gas exhaust union with check valve and flue gas
analysis outlet
10
Manual diverting valve
11
Return shut-off valve
12
Gas cock
13
Delivery sensor traps
14
Safety valve
AA
Air inlet
SF
Exhaust flue duct
SC
Condensate outlet
MI
Central heating flow
RI
Central heating return
GAS
Gas supply