Navien NPE-180A Service Manual page 29

External Recirculation Mode
To use the external recirculation mode:
1. Connect the water supply to support recirculation. Refer to the
"Installation Manual (page 20)".
2. Set the 2-way valve inside the water heater to "EXT. "
3. Set the front panel DIP switches at the far left (set of ten) to:
1—OFF; 2—ON.
ON
1 2 3 4 5
28 NPE Service Manual
ON
6 7 8 9 10
The following diagram shows the external recirculation flow for
pre-heating:
Primary Heat Exchanger
Buffer
Secondary Heat Exchanger
Tank
Circulation
2-Way
Pump
Valve
Closed
Hot
Recirculation
Water
Water Supply
Supply
External Recirculation Mode
Flow
Sensor
Check
Valve
Water
Adjustment
Valve
Domestic
Water
Supply
Version 2.21