26 Installing the Water Heater
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 2-ON.
1
2
3
4 5
6 7
8
9
10
ON
ON
OFF
NOTICE
Do NOT remove the pre-installed recirculation
cap if the internal recirculation mode is used.
Any resulting water leaks may cause property
damage.
3.4.1 Selecting a Recirculation Mode
On all NHW700 AI/AE model water heaters, you
can choose from two pre-heating modes: internal
recirculation mode or external recirculation mode.
To select a recirculation mode, you must adjust the
recirculation settings on the front panel and set the
position of the 2-way valve inside the water heater.
When the optional ComfortFlow recirculation mode
is activated, energy consumption increases because
the water heater operates to maintain the water
temperature within the circulation loop. You can
use the Navien Intelligent Preheating feature, set
the weekly timer, or activate the HotButton feature
(additional accessories required) to reduce energy
consumption.
The recirculation feature of the NHW700 AI/AE
models has three performance advantages:
●
Lower Minimum Flow Rate is needed to produce
hot water.
●
Resolves hot/cold/hot stacking issue—the “cold
water sandwich“ effect.
●
Quicker hot water delivery to fixtures, which
results in less water wasted.
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.
If PEX is used for the water piping,
consult with the pipe and fittings
manufacturer for sizing and equivalent
pressure drop information.
