Navien NCB-180, Service Manual

Page: 131 / 149

128 NCB Service Manual Version 1.0
5. Remove the stainless nut, fastener and circulation pump
wiring connector (Figure 22).
Figure 22
6. Carefully remove the pump.
Figure 23
7. Remove the air vent..
Figure 24
8. Replace with the new circulation pump (or Air Vent).
9. Place the new pump back into its original position and
ensure that all connections are tightly sealed.
10. Secure the pump with the stainless steel clip and the 2
fixing screws.
11. Reinstall the pump drain plug at the bottom of the unit.
12. Reconnect the wiring connector at the pump.
13. Install the Main PCB back onto the unit by using the four
screws.
14. Turn on water supply, power supply, and gas supply to
the unit.
15. Open a hot water tap and ensure that there are no leaks
at the pump connections.
16. Open the air vent on top of pump to release air within
the system.
NOTE
Always use proper O-rings at the pump connection to
ensure tight seals
6.2.11 3-way Valve
1. Turn off the gas supply to the unit.
2. Turn off the 120V power supply to the unit.
3. Turn off the water supply to the unit. Drain all water
from the appliance.
4. Remove the Circulation Pump (see page 127)
5. Remove the fastener and two screws on the 3-way valve.
Figure 25