Navien NCB500-2S/37K Service Manual page 110

6. Loosen the three screws holding the front panel and remove
the front panel.
When removing the front panel, label all wires and
Note
make sure all wires are disconnected.
7. Use a Phillips screwdriver to remove the two screws where
gas inlet pipe is attached to the fan motor assembly. Loosen
the hex nut located above the gas valve and remove the gas
pipe.
Remove
2 screws
here
Loosen
the hex
nut here
8. Remove the screw connecting the fan motor assembly
and the mixing chamber, and then remove the fan motor
assembly.
2
9. Remove the four bolts securing the chamber brackets.
1
Inspection and Maintenance Schedule 109