E/O, 305I, 505E/O, 505I - A.O. Smith GTS-305-NE Service Manual

Component Replacement Instructions
Gas Control Assembly
12. Attach wire harness to the 4 solenoids as shown in Figure 3 below.
S V 2 b a l k c / b
SV0 black / pink
Figure 3
13. Install the gas manifold using 2 new packings (included in kit) between the manifold and the heat
exchanger. Replace the two circular gaskets (included in kit) in the gas valve (Figure 5).
Upper packing
Lower packing
(U shaped)
14. Start the three screws that attach the gas manifold to the gas valve. Tighten the six screws that hold
the gas manifold to the combustion chamber. Finish tightening the three screws that hold the gas
manifold to the gas valve.
15. Attach wiring harness connector (black & brown wires) to the gas manifold.
16. Attach ignition line.
17. Perform the Gas Pressure Setting Procedure.
On-Demand Gas Tankless Water Heater Service Manual

305e/o, 305i, 505e/o, 505i

u l e
Figure 4
S V 1 b a l k c / y e o l l w
POV pink / pink
(connector not shown)
Figure 5
21
Circular gaskets (re-use)
in gas valve