A.O. Smith EQ 115 G Installation And User Instructions Manual page 12

See Figure 4.
A.O. Smith water heaters are tested to
a maximum pressure of 12 bar and a
maximum working pressure of 8 bar.
Figure 4 - Connection diagram
(unvented system)
1) Manual gas valve
2) Stop valve
3) Expansion vessel
4) T&P safety valve
5) Non return valve
6) Circulation pump
7) Drain valve
12
8) Pressure limiting valve
9) Expansion valve
A ) Gas supply
B) Hot water delivery
C) Cold water inlet
D) Hot water taps
E) Return circulation
AOS 0581