Connecting The Water Supply - Navien NPE-180A Installation Manual

2. Open a hot water faucet. The water heater should turn on and
the gas in the gas supply line will be purged.
3. Leave the faucet on until the water heater shuts down due to a
lack of gas supply, and then turn off the hot water faucet.
4. Remove the water heater front cover by loosening the
4 Phillips head screws securing it to the case.
5. Loosen the screw indicated in the figure below and connect a
manometer to the pressure port. Reset the manometer to zero
before use.
6. Re-open the manual gas valve and check for leaks.
7. Open multiple fixtures that have high flow rates, such as
bathtub and shower faucets, to ramp the water heater up to its
maximum firing rate.
Digital pressure
manometer
8. When the water heater reaches its maximum firing rate, check
the inlet gas pressure reading on the manometer. The gas
pressure must fall within the ranges specified on page 18.

3.4 Connecting the Water Supply

The water fittings on the water heater are 3/4". If the installation
site only has 1/2" plumbing throughout, it is not necessary to
upsize the water lines to 3/4", if you are installing a single water
heater. When installing multiple water heaters, the number of
water heaters and pipe sizing required will depend on the total
hot water demand. For information about pipe sizing for multiple
water heaters, refer to "4.1.1 Piping Sizes and Considerations" on
page 37.
When connecting the water supply, follow these guidelines:
Do not remove the factory installed recirculation inlet cap unless
a return line is connected to this fitting. Water leakage will occur
if this cap is loose or missing ("A" model only).
Use only pipes, fittings, valves, and other components, such as
solder, that are approved for use in potable water systems.
Tighten the water heater connection valves with care to avoid
damage.
We recommend using unions and manual shut-off valves on the
cold water inlet, DHW outlet, and recirculation water inlet.
Strive to make the hot water piping system as short as possible,
to deliver hot water to the fixtures more quickly.
To conserve water and energy, insulate all water piping—
especially the hot and recirculation water lines. Never cover the
drain or pressure relief valve. If the water heater is installed in
a closed water supply system, such as one having a backflow
preventer in the cold water supply line, means shall be provided
to control thermal expansion. Contact the water supplier or local
plumbing inspector for information about how to control this
situation.
After installing the water heater, clean the inlet water filter that
is located inside the cold water inlet, and then test the water
heater for proper flow and inspect for leaks. Instruct the water
heater owner that the filter must be cleaned periodically to
maintain proper water flow.
Installing the Water Heater 19