A.O. Smith ST 3000 - Manual (Page 5)

Back-up
element
6
1 = drain (on small tanks only)
2 = valve
3 = check valve
4 = pressure relive valve
5 = circulation pump sanitary water
6 = temperature sensor for boiler three way valve
A = circulation line
B = warm water
C = cold water
E = boiler water hot
F = boiler water return
Optional backup elements are available for field installation up to 6 kW input. Models with fixed internal heat exchanger
are also available.
5