1-17
INSTALLATION
TANKLESS WATER HEATER 199
Vent terminal clearance minimums are as follows:
CANADIAN
INSTALLATIONS
1, 3
US
INSTALLATIONS
2, 3
A= Clearance above grade,
veranda, porch, deck, or balcony
12 in (30 cm)
12 in (30 cm)
B= Clearance to window or door
that may be opened
36 in (91 cm) for appliances
over 100,000 Btuh (30kW)
12 in (30 cm)
C= Clearance to permanently
closed window
* (Recommend minimum 1
ft (30 cm))
* (Recommend minimum 1
ft (30 cm))
D= Vertical clearance to
ventilated soffit located above
the terminal within a horizontal
distance of 2 ft (61 cm) from the
center line of the terminal.
* (Recommend minimum 2
ft (61 cm))
* (Recommend minimum 2
ft (61 cm))
E= Clearance to unventilated
soffit
*(Recommend minimum 1 ft
(30 cm))
* (Recommend minimum 1
ft (30 cm))
F= Clearance to outside corner
* (Recommend minimum 4
ft (122 cm))
* (Recommend minimum 4
ft (122 cm))
G= Clearance to inside corner
* (Recommend minimum 4
ft (122 cm))
* (Recommend minimum 4
ft (122 cm))
H= Clearance to each side of
center line extended above
meter/regulator assembly
3 ft (91 cm) within a height
of 15 ft (4.6m)
*
I= Clearance to service regulator
vent outlet
3 ft (91 cm)
*
J= Clearance to nonmechanical
air supply inlet to building or the
combustion air inlet to any other
appliance
36 in (91 cm) for appliances
over 100,000 Btuh (30 kW)
12 in (30cm)
K= Clearance to a mechanical
air supply inlet
6 ft (1.83 m)
3 ft (91 cm) above if within
10 ft (3 m) horizontally
L= Clearance above paved
sidewalk or paved driveway
located on public property
7 ft (2.13 m) †
Vents cannot be located
above public walkways
or other areas where
condensate or vapor can
cause a nuisance or hazard.
M= Clearance under veranda,
porch deck, or balcony
12 in (30 cm) ‡
*
Clearance to adjacent wall
6 ft (1.83 m)
6 ft (1.83 m)
1 In accordance with the current CSA B149.1 Natural Gas and Propane Installation Code
2 In accordance with the current ANSI Z223.1 / NFPA 54 National Fuel Gas Code
3 If locally adopted installation codes specify clearances different than those illustrated, then the most stringent shall
apply.
† A vent shall not terminate directly above a sidewalk or paved driveway that is located between two single family
dwellings and serves both dwellings.
‡ Permitted only if veranda, porch, deck, or balcony is fully open on a minimum of two sides beneath the floor.
* Clearance in accordance with local installation codes and the requirements of the gas supplier. The minimum distance
from adjacent public walkways, adjacent buildings, openable windows, and building openings shall not be less than
those values specified in the National Fuel Gas Code, ANSI Z223.1/NFPA 54, and/or the Natural Gas and Propane
Installation Code, CSA B149.1
WARNING
- In addition to preventing
ingestion of chemical
contaminants, care must
be taken to ensure air
intake terminals are not
installed in locations
where contamination might
occur due to ingestion of
particulate foreign material
(dust, dirt and debris).
- Intake air openings must
be configured such that
rain or other forms of
moisture cannot enter the
air intake piping system.
Otherwise serious damage
to the unit may result.
NOTE
Care must be taken when
installing air intake piping
to ensure that a “trap” is
not formed in the piping
so as to allow a build-up
of water, and blockage of
intake air.
Such blockage will result
in a unit’s safety shut-
down.