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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
38
Installing the Water Heater
Inside
corner detail
Legend:
Vent terminal
Air supply inlet
Area where terminal is not permitted
Direct Vent Installations
12 in (30 cm)
12 in (30 cm)
12 in (30 cm)*
3 ft (91 cm)*
3 ft (91 cm)*
2 ft (61 cm)*
12 in (30 cm)*
3 ft (91 cm) within a height of 15 ft (4.6 m)*
3 ft (91 cm)*
12 in (30 cm)
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*
12 in (30 cm) - open on 3 sides*
Regulator vent outlet In
the event no regulator
is present, H and I can
be disregarded.
1
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