Navien NPE-240A Installation Manual

22 Installing the Water Heater
CAUTION
Do not remove recirculation cap. (Internal Recirculation Mode)
The following diagram shows the internal recirculation flow for
pre-heating:
Internal Recirculation Mode
Primary Heat Exchanger
Secondary Heat Exchanger
Buffer
Tank
Flow
Sensor
Domestic Water
Supply
Hot Water
Supply
Check
Valve
Water
Adjustment
Valve
2-Way
Valve
Open
Circulation
Pump
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 21.
2. Set the 2-way valve inside the water heater to “EXT.“
Note
When using external recirculation mode with the
built-in pump, observe the following maximum
recirculation pipe lengths including fittings (
3
/
4
in pipe
is recommended):
-
1
/
2
in Copper Pipe- 100 ft (30 m) of equivalent length
-
3
/
4
in Copper Pipe- 500 ft (150 m) of equivalent length
Lengths in excess of these limits will require an
external recirculation pump.
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.
ONON
1 2 3 4 5 6 7 8 9 10

Navien NPE-240A Specifications

General

Type	Tankless
Fuel Type	Natural Gas or Propane
Energy Factor	0.97
Energy Efficiency	97%
Voltage	120V
Ignition Type	Electronic
Maximum Input	199, 900 BTU/h
Water Connection Size	3/4"
Gas Connection Size	3/4"
Warranty	15-year on heat exchangers, 5-year on parts, 1-year on labor
Dimensions	17.3" W x 13.2" D x 27.4" H