Aps; Main Gas Valve - Navien NCB-700-2S+/42K Service Manual

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.
Confirm that the new air pressure sensor is in the
Note
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
Replacement of Parts 109