Main Gas Valve - Navien NCB-180 Service Manual

5. Remove the hose from the air pressure sensor.
Figure 12
6. Remove the 2 screws that attaches the air pressure
sensor to the burner assembly.
7. Pull out the air pressure sensor.
8. Replace the old air pressure sensor with the new part.
9. Reattach the air pressure sensor hose.
10. Connect the air pressure sensor wiring connector.
11. Place the front panel back onto the unit and secure it
using the 4 screws.
12. Turn on water supply, power supply, and gas supply to
the unit.
NOTE
Confirm that the new air pressure sensor is in the proper
position before turning the unit back on.

6.2.7 Main Gas Valve

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 PCB (See page 121)
5. Remove the 2 screws and disconnect the wiring
connector at the gas valve.
Figure 13
6. Remove the 2 screws located at the bottom of the unit
that are attached to the gas valve.
Figure 14
Remove the 8 screws directly on the bottom of the gas valve to
remove the gas pipe.
Figure 15