Navien NFC-175, Service Manual

Page: 124 / 138

124 NFC Service Manual
Version 1.0
5. Disconnect the wiring connector from the Ignition
Transformer.
Figure 11
6. Remove the 2 screws from the Ignition Transformer.
Figure 12
7. Pull out the Ignition Transformer.
8. Replace the old Ignition Transformer with the new part, and
then use the 2 screws to secure the part.
9. Reconnect the Ignition Transformer insulated cables to the
igniter probe connectors.
10. Reattach the wiring connectors from the Ignition Transformer.
11. Turn on water supply, power supply, and gas supply to the
unit.
Note
Verify that the Ignition Transformer insulated cables are
firmly connected to the igniter probe connectors.
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. Remove the air pressure sensor wiring connector (Figure 13).
Figure 13
5. Remove the hose from the air pressure sensor.
Figure 14
6. Remove the 2 screws that attach 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.