E/O (Asme) - A.O. Smith GTS-305-NE Service Manual

Component Replacement Instructions
Heat Exchanger
15. Remove the fan assembly (4 screws) and
install it on the new heat exchanger. (Figure 71)
16. Remove the flue outlet (6 screws) and install it
on the new heat exchanger. (Figure 72)
17. Install the largest O-ring (included in kit) over
the water outlet tube and the two smaller O-
rings (included in kit) over the water inlet
tubes. (Figure 71)
18. Slide the fusible link between the water outlet
and inlet tubes and onto the new heat
exchanger. (Figure 71)
19. Attach brackets at the back and side holding
the fusible link.
20. Install the 4 screws at the top and bottom of
the heat exchanger to the casing. (Figure 70)
21. Insert the burner and place the burner cover
plate into position. Attach the burner cover
plate first with 9 screws and then attach the
burner with 2 screws. (Figure 69)
22. Replace the electrode gasket. (Figure 73)
23. Make sure that the black gasket (Figure 74) is
intact on the gas control assembly. Replace
the lower and upper gaskets (included in kit)
for the manifold plate removing any residue.
(Figure 75)
24. Attach the electrical connector to the ignitor
on the manifold and attach the gas manifold
with 2 machine screws at the gas control
assembly. (Figure 68)
25. Attach the gas manifold with 5 screws at heat
exchanger. (Figure 68)
26. Connect wire harness attachments.
27. Attach the ignition line at the burner cover
plate.
28. Attach the 3 electrical connectors to the
solenoid valves.
29. Attach the wire harness to the fan assembly
(white, yellow, black, red wires).
30. Attach the brackets to the water line
connections. (Figure 68)
31. Install the front panel using 4 screws. Turn on
the water supply, power supply, and gas
supply. Check for gas leaks.
On-Demand Gas Tankless Water Heater Service Manual

705e/o (ASME)

4 locations
Figure 71
Figure 72
Figure 73
Figure 74
Figure 75
51
Water
Water inlet
outlet tube
tubes
Electrode
Gasket
Gasket
Gaskets