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

Component Replacement Instructions
Fan
1. Turn off the gas supply.
2. Turn off the 120 V power supply.
3. Turn off the water supply.
4. Remove four screws securing the front panel. Remove front panel.
5. Disconnect wire harness at the fan assembly. Disconnect the air temperature thermistor (two white
wires) at the connection with the white and orange wires within the wire bundle.
6. Pull out the harness attached to the solenoid on the manifold to make room to pull out the fan as-
sembly.
7. Loosen the ducting from the fan assembly by pinching open the metal clamp.
Ducting and
metal clamp
water flow servo
assembly
connection
Water outlet
connection
8. Remove the two screws that attach the fan assembly to the bottom of the burner.
9. Pull out the fan assembly.
10. Install the fan assembly by inserting the tab on the fan assembly into the slot at the base of the heat
exchanger and attaching with two screws.
11. Push ducting over fan assembly inlet and secure with metal clamp.
12. Attach the wire harness to the solenoid on the gas manifold (brown, black wires).
13. Attach the wire harness to the fan assembly (white, yellow, black, red wires).
14. Attach the air temperature thermistor (white, white wires) to the wire harness.
15. Install front panel using 4 screws.
16. Turn on water supply, power supply, and gas supply.
On-Demand Gas Tankless Water Heater Service Manual

305i, 505i

2 screws
25
Figure 12
Solenoid on the manifold
Wire harness connection
on the fan assembly
Wire harness bundle
(air temperature
thermistor connection to
orange / white wires)