Navien NPE-180A Installation Manual page 22

Internal Recirculation Mode
To use the internal recirculation mode:
1. Connect the water supply.
2. Set the 2-way valve inside the water heater to "INT. "
3. Set the front panel DIP switches at the far left (set of ten) to:
1—ON; 2—OFF.
ON
1 2 3 4 5
CAUTION
Do not remove recirculation cap. (Internal Recirculation Mode)
ON
6 7 8 9 10
The following diagram shows the internal recirculation flow for
pre-heating:
Primary Heat Exchanger
Buffer
Secondary Heat Exchanger
Tank
2-Way Circulation
Pump
Valve
Open
Hot Water
Supply
Internal Recirculation Mode
External Recirculation Mode
To use the external recirculation mode:
1. Connect the water supply to support recirculation. Refer to the
"[NPE-180A/ 210A/ 240A]" diagram on page 20.
2. Set the 2-way valve inside the water heater to "EXT. "
Flow
Sensor
Check
Valve
Water
Adjustment
Valve
Domestic Water
Supply
Installing the Water Heater 21