Fuse; Fan Motor (Combustion Air) - Navien NCB-150E Service Manual

7. Remove the old PCB and replace it with the new part.
8. Reattach all wiring connectors to the PCB.
9. Set the proper DIP S/W settings on the PCB (refer to page 131).
10. Reinstall the PCB and Front Panel using the 7 screws previously
removed.
11. Turn on the water and gas supplies, then reconnect the power
supply to the unit.
NOTE
All wiring harness connections to the PCB should match in
color and pintypes. Do not use excessive force when removing
the connectors as this may cause damage to the PCB.

6.2.2 Fuse

1. Turn off the gas supply to the unit.
2. Disconnect the unit from the power supply.
3. Locate the fuse housing shown in Figure 3 below. Open the
housing to expose the fuse.
Figure 3
4. Replace the old fuse with the new part.
5. Ensure that the new fuse is of an equivalent rating and that it is
properly fixed inside the housing.
6. Close the fuse housing.
7. Turn on water supply, power supply, and gas supply to the
unit.

6.2.3 Fan Motor (Combustion Air)

1. Turn off the gas supply to the unit.
2. Disconnect the unit from the power supply.
3. Turn off the water supply to the unit.
4. Remove the mounting screw from the fan assembly as shown
in Figure 4 below.
5. Remove the fan assembly bracket with the attached intake
port.
Figure 4
6. Disconnect the wiring connector from the fan assembly, and
then remove the 4 screws from the gas valve connection as
shown in Figure 5 below.
Figure 5
7. Pull out the fan assembly and remove the 4 screws that secure
the air intake port to the fan assembly.
Replacement of Parts 135