11
The following information should be used for determining the proper location of the vent terminal
for direct vent tankless water heaters.
V VENT TERMINAL
X
AIR SUPPLY INLET
AREA WHERE TERMINAL IS NOT PERMITTED
Horizontal Vent Terminal Location
Canadian Installations
1
US Installations
2
1 In accordance with current CAN/CGA-B149 Installation Codes.
2 In accordance with current ANSI Z223.1/ NFPA 54 National Fuel Gas Code.
+ A vent shall not terminate directly above a sidewalk or paved driveway that is located between two single family
dwellings and serves both dwellings.
* If clearances are not specified then follow local installation codes and the requirement of the gas supplier.
** For condensing appliances: The vent for this appliance shall not terminate over public walkways, near soffit
vents, crawl space vents, of other areas where condensate or vapor could create a nuisance, hazard, or cause
property damage. Where condensate or vapor could cause damage or could be detrimental to the operation of
regulators, relief valves, or other equipment.
H = Clearance to each side of center line
extended meter/regulator assembly.
above
3 feet (91 cm) within a height 15 feet
(4.57 m) above the meter/regulator
assembly.
*
I = Clearance to service regulator vent
outlet.
3 feet (91 cm)
*
J = Clearance to nonmechanical air
supply inlet to the combustion air
inlet to any building or other
appliance.
6 inches (15 cm) for appliances < 10,000
Btuh (3 kW), 12 inches (30 cm) for
appliances > 10,000 Btuh (3kW) and
< 100,000 Btuh (30kW), 36 inches (91
cm) for appliances > 100,000 Btuh
(30kW).
6 inches (15 cm) for appliances < 10,000
Btuh (3 kW), 9 inches (23 cm) for
appliances > 10,000 Btuh (3 kW) and
< 50,000 Btuh (15 kW), 12 inches
(30 cm) for appliances > 50,000 Btuh
(15 kW).
K = Clearance to mechanical air supply
inlet.
6 feet (1.83 m)
3 feet (91 cm) above if within 10 feet
(3 m) horizontally.
L = Clearance above paved side walk or
paved driveway located on public
property.
Not allowed
Not allowed
M = Clearance under veranda, porch,
deck or balcony.
Not allowed
Not allowed
A= Clearance above grade, veranda,
porch, deck or balcony.
12 inches (30 cm) above anticipated
snow level.
12 inches (30 cm) above anticipated
snow level.
B= Clearance to window or door that
may be opened.
6 inches (15 cm) for appliances < 10,000
Btuh (3 kW), 12 inches (30 cm) for
appliances > 10,000 Btuh (3kW) and <
100,000 Btuh (30kW), 36 inches (91 cm)
for appliances > 100,000 Btuh (30kW).
6 inches (15 cm) for appliances < 10,000
Btuh (3 kW), 9 inches (23 cm) for
appliances > 10,000 Btuh (3 kW) and
< 50,000 Btuh (15 kW), 12 inches
(30 cm) for appliances > 50,000 Btuh
(15 kW).
C= Clearance to permanently closed
window.
*
*
D= Vertical Clearance to ventilated soffit
located above the terminal within a
horizontal distance of 2 feet (61 cm)
from the center line of the terminal.
*
*
E= Clearance to unventilated soffit.
*
*
F= Clearance to outside corner.
*
*
G= Clearance to inside corner.
*
*
