A.O. Smith 185874-001 Instruction Manual page 15

9. Remove flange nuts holding inner door in place with 3/8" nut
driver, see Figure 13.
fIGure 13.
10. Loosen flare nut "T" holding thermocouple to bottom of gas valve
with 3/8" open-end wrench and pull down to remove, see Figure
14.
11. Loosen flare nut "P" holding pilot line to bottom of gas valve
with 7/16" open-end wrench and pull tube down to remove, see
Figure 14.
12. Loosen flange nut "B" holding burner tube to bottom of gas valve
with 3/4" open-end wrench and pull down to remove, see Figure
14.
fIGure 14.
13. Grasp burner tube and remove burner assembly through inner
door opening.
14. To remove the natural gas pilot assembly, remove the Phillips-
head screw holding the TCO bracket to the burner tube bracket,
see Figure 15.
fIGure 15.
15. Remove the Phillips-head screw holding the pilot bracket to the
burner head, see Figure 16.
16. Remove the two Phillips-head screws holding the natural burner
head to the burner tube assembly, see Figure 17.
17. Using 3/8" boxed-end wrench remove the natural gas burner
orifice "O" from the burner tube. Install burner orifice marked
"LP" and tighten securely, see Figure 17.
18. Locate and install the propane burner head to the burner tube
using the two Phillips-head screws, see Figure 17.
19. Push the natural gas pilot assembly grommet out of the inner
door towards the combustion chamber.
20. To install the propane pilot assembly, put the igniter wire,
thermostat lead, and pilot tube through the inner door hole.
Reinstall the Phillips-head screw securing the TCO bracket to
the burner tube. Reinstall the Phillips-head screw securing the
pilot assembly to the burner head bracket.
21. Push the grommet into the inner door hole making sure the door
fits into the groove in the grommet.
22. Reinstall the burner assembly through the door opening being
careful not to damage the door gasket on the studs. Position
end of burner tube inside bracket as shown in Figure 18.
15
fIGure 16.
fIGure 17.
fIGure 18.