Navien NPN Installation & Operation Manual page 36

3.5.2 Maintaining Clearances
Terminal clearances
Maintain the following venting clearances, as required by ANSI Z21.10.3 and the National Fuel Gas Code, ANSI
Z223.1/NFPA 54:
For indoor models (direct vent)
Ref Description
A Clearance above grade, veranda, porch, deck, or balcony
B Clearance to window or door that may be opened
C Clearance to permanently closed window
Vertical clearance to ventilated soffit located above the terminal
D within a horizontal distance of 2 ft (61 cm) from the center line
of the terminal
E Clearance to unventilated soffit
F Clearance to outside corner
G Clearance to inside corner
Clearance to each side of center line extended above meter/
H
regulator assembly
I Clearance to service regulator vent outlet
Clearance to nonmechanical air supply inlet to building or the
J
combustion air inlet to any other appliance
K Clearance to a mechanical air supply inlet
Clearance above paved sidewalk or paved driveway located on
L
public property
M Clearance under veranda, porch deck, or balcony
Inside
corner detail
Legend:
Vent terminal
Air supply inlet
Area where terminal is not permitted
Direct Vent Installations
12 in (30 cm)
●
●
●
As specified by the manufacturer*
As specified by the manufacturer*
As specified by the manufacturer*
As specified by the manufacturer*
As specified by the manufacturer*
As specified by the manufacturer*
As specified by the manufacturer*
●
●
●
3 ft (91 cm) above if within 10 ft (3 m) horizontally
7 ft (2.13 m) for mechanical draft systems (Category
I appliances). Vents for Category II and IV appliances
cannot be located above public walkways or other
areas where condensate or vapor can cause a
nuisance or hazard*
As specified by the manufacturer*
Regulator vent outlet In
the event no regulator
is present, H and I can
be disregarded.
1
6 in (15 cm) for appliances ≤ 10,000 Btuh (3 kW)
9 in (23 cm) for appliances > 10,000 Btuh (3 kW)
and ≤ 50,000 Btuh (15 kW)
12 in (30 cm) for appliances > 50,000 Btuh (15 kW)
6 in (15 cm) for appliances ≤ 10,000 Btuh (3 kW)
9 in (23 cm) for appliances > 10,000 Btuh (3 kW)
and ≤ 50,000 Btuh (15 kW)
12 in (30 cm) for appliances > 50,000 Btuh (15 kW)
Installing the Water Heater 35