Navien NPN Installation & Operation Manual page 28

4. Connect the external pump wiring connector to
the connector socket on the PCB (TB1).
5. Put the PCB box back in its original place and
secure it using the 2 mounting screws.
6. Remove the plastic insulation from the
external pump wire with a wire stripper before
connecting it to the pump.
7. Connect the External Pump Wire to the proper
wires from the pump junction box.
WARNING
To avoid the danger of electric shock, turn on
the water heater ONLY after connecting the
wire to the external pump.
TB1
8. Locate the 10-switch DIP (SW1) on the front
panel and turn on the proper switches based
on the desired recirculation setting (see
Recirculation Dipswitch Settings below).
ON
[NPN-160U/180U/199U]
[NPN-120E/160E/180E/199E]
ON
1 2 3 4 5 6 7 8 9 10 1 2
ON
1 2 3 4 5 6 7 8 9 10
Installing the Water Heater 27