Navien NPE-240A Installation Manual

30 Installing the Water Heater
2. Provide two openings to allow for circulation of combustion air
as specified by ANSI Z223.1/NFPA 54 or CAN/CGA B-149.1:
Maximum
Input
(BTU/H)
Outdoor
make up air is
provided,
a minimum
free area of
1 in
2
per 4,000
BTU/H
Indoor make
up air is
provided,
a minimum
free area of
1 in
2
per 1,000
BTU/H
NPE-150S
120,000
30 in
2
10 in (W) x 3 in
(H) or 6 in
round
120 in
2
11 in (W) x
11 in (H)
NPE-180A
NPE-180S
150,000
40 in
2
10 in (W) x 4 in
(H) or 7 in
round
150 in
2
12
1
/
4
in (W) x
12
1
/
4
in (H)
NPE-210A
NPE-210S
180,000
45 in
2
10 in (W) x 5 in
(H) or 8 in
round
180 in
2
13
1
/
4
in (W) x
13
1
/
4
in (H)
NPE-240A
NPE-240S
199,900
50 in
2
10 in (W) x 5 in
(H) or 8 in
round
199 in
2
14
1
/
4
in (W) x
14
1
/
4
in (H)
Non-Direct Venting (Single Pipe)
If, at any time, the installation location could experience negative
pressure, there is a possibility of back drafting cold air through
the water heater’s heat exchanger. This situation could lead to
the freezing of the heat exchanger and malfunction of the water
heater.
However, building codes in most jurisdictions disallow negative
pressures in residences. In a home with a well-balanced air supply,
the heat exchanger should not be in danger of freezing. Because
the cause of back drafting is not considered a manufacturing
problem, any freezing damage which occurs from back drafting
will not be covered by the Navien warranty. If there is any question
about the possibility of back drafting in the installation location,
use a direct venting system for the water heater.
When installed in a manufactured home (mobile home), all
combustion air must be supplied from the outdoors as described
on page28.
When using non-direct venting, maintain non-direct vent
clearances shown on page31 as required by ANSI Z21.10.3 and
the National Fuel Gas Code, ANSI Z223.1/NFPA 54, and CAN/
CSA B149.1 Natural Gas And Propane Installation Code.
To use non-direct venting for the water heater:
1. Insert the termination end cap into the intake air duct. Do not
glue the end cap, to allow for easy removal and cleaning of the
cap.
Vent termination cap 2 in
Coupling 2 in
Pipe 2 in

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