Navien NCB-24LSWE, Service Manual

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126 NCB Service Manual Version 1.0
6.2.6 APS
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. Refer to figure11 and remove the air pressure sensor
wiring connector.
Figure 11
5. Remove the hose from the air pressure sensor.
Figure 12
6. Remove the 2 screws that mount the air pressure
sensor on 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.

-Remove the 4 screws from bottom front panel
bracket and upper front panel bracket.
Figure 13
Disconnect wiring connector from the main PCB.
4. Remove the 2 screws and disconnect the wiring
connector at the gas valve.
Figure 13