A.O. Smith GTS-305-NE Service Manual page 35

Component Replacement Instructions
Heat Exchanger
1. Turn off the gas supply.
2. Turn off the 120 V power supply.
3. Turn off the water supply. Drain all water
from the appliance.
4. Remove four screws securing the front panel.
Remove front panel.
Remove Fan Assembly (Figure 29)
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 assembly.
7. Remove the 2 screws that attach the fan
assembly to the bottom of the burner.
8. Pull out the fan assembly.
Disconnect Water Lines (Figure 30)
9. Remove 1 screw from the water outlet
bracket. Remove the bracket by rotating and
moving it up toward the bend in the tube
where the diameter is smaller.
10. Remove 1 screw and 1 bracket at the water
flow servo assembly.
On-Demand Gas Tankless Water Heater Service Manual
305e
Figure 28
Figure 29
Figure 30
Water outlet
connection
35
Burner cover
plate
Gas Manifold
PC Board
Gas Control
Valve
Fan Assembly
2 screws
Wire
harness
connection
Water flow servo
assembly connection
Solenoid