Navien NPE-180A Installation Manual page 23

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
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
ON
6 7 8 9 10
Flow
Sensor
Check
Valve
Water
Adjustment
Valve
Domestic
Water
Supply
3.4.3 External Pump Wire Connection
An external pump may be connected to the water heater for
recirculation applications. When selecting a circulator, it shall be
sized to maintain a flow of 2-4 GPM through the water heater.
Follow the instructions below when connecting the pump wire
accessory to the PCB.
WARNING
Failure to follow the instructions below may result in property
damage, personal injury or death. To avoid the danger of
electric shock, make sure that the water heater is turned off
before connecting the wire to the PCB.
<Specications>
Maximum Power Consumption: 150 W, 1.5 A
Length: 6 ft (183 cm)
Ú
When using a pump with larger power requirements than the listed
specication above, a relay should be used to ensure proper operation.
1. Remove the water heater front cover by loosening the
4 Phillips head screws securing it to the case.
2. Locate the power switch on the right side of the front panel
and switch the system off.
Turn the switch off.
Installing the Water Heater 23