A.O. Smith BTX 100 Service Handbook page 18

burner assembly removal
1. Follow the instructions to remove the Combustion Blower beginning on page 14.
2. Remove the Blower discharge orifice from the top of the Burner Adapter.
3. unplug the Burner Adapter wiring harness; three male/female spade connections for the Igniter and
Flame Sensor behind the CCB enclosure, see Figure 10 on page 13.
4. using a socket wrench with a 1/2 inch deep well socket remove the four 1/2 inch nuts from the studs
holding the Burner Adapter in place, see Figure 16 on page 17 and Figure 17 on page 17.
5. Slide the Burner ground wire eyelet connector up and off of the 1/2 inch stud it is secured to. This ground
wire must be put back in place when reinstalling the Burner Assembly, see Figure 16 on page 17.
6. Ensure there are not any loose parts, tools, screws or objects of any kind on top of the water heater
before removing the Burner Assembly. If any loose objects present store them in a different location.
7. Carefully lift the Burner Assembly straight up and out of the water heater's heat exchanger opening, see
Figure 17 on page 17.
8. Inspect the Flame Sensor and its ceramic insulator for cracks and wear. Replace the Flame Sensor if it
shows any sign of damage or excessive wear, see Figure 19 on page 19.
9. Ensure the Flame Sensor is not touching the Burner surface, the gap should be approximately 1/2 inch.
10. Ensure the Flame Sensor mounting screw is tight.
11. Always clean the flame sensor with ultra fine steel wool while the Burner Assembly is out. do not use a
harsh abrasives such as sand paper to clean the Flame Sensor.
12. Inspect the Burner Adapter wiring harness and wiring harness grommet, replace the wring harness if it
shows any sign of excessive wear or damage, see Figure 8 on page 12 and Figure 12 on page 13.
13. Inspect the Igniter. Replace the Igniter if it shows any sign of damage or excessive wear.
14. Ensure the Igniter mounting screw is tight.
15. Remove the four 5/16 inch hex head machine screws holding the Burner to the Burner Adapter and
remove the Burner from the Burner Adapter. See Figure 5 on page 9.
16. Inspect the Burner. Ensure there are not any debris inside the Burner, see the Service notes on page 5.
Replace the Burner if it is damaged or clogged with debris.
16
Figure 15
Servicing should only be performed by a Qualified Service Agent