A.O. Smith GDVT instruction manual Combustion AIR and Ventilation, Vent Terminal Clearances

COMBUSTION AIR AND VENTILATION

When determining the installation location for a direct vent water heater, snow accumulation and drifting should be considered in areas where applicable.

VENT TERMINAL CLEARANCES

The vent system must terminate so that proper clearances are maintained as cited in local codes or the current edition of the National Fuel Gas Code ANSI Z223.1/NFPA 54 as follows:

*Minimum 9 in. (23 cm) for appliances with 10,000 btuh (3 Kw) to 50,000 btuh

(15 Kw) inputs and 12 in. (30 cm) for appliances greater than 50,000 btuh (15 Kw) to

a window or door that may be opened

Minimum 18 in. (46 cm)
	Minimum 3 ft. (91 cm) within a
12 in. (30 cm)	height of 15 ft. (4.6 cm) above
	meter/regulator assembly
above grade or
anticipated snow
level	Minimum 3 ft. (91 cm) clearance
	to service regulator vent outlet

12 in. (30 cm)

from soffit

Minimum

7 ft. (2.3 m)

above

public sidewalk

or paved driveway

(see footnote 2)

Minimum

12 in. (30 cm)

from sides, above or below a permanently closed window or door

VENT TERMINAL

*

AIR SUPPLY INLET

Minimum		Minimum 12 in. (30 cm)
2 ft. (61 cm)		under veranda, porch,
from outside		deck or balcony
corner		(see footnote 1)
*	*	Minimum
		3 ft. (91 cm)
		above if within
		10 ft. (3 m)
*		horizontally to
		a mechanical air

supply inlet

*	Minimum 9 in. (23 cm) for appliances with 10,000 btuh (3 Kw)
	to 50,000 btuh (15 Kw) inputs and 12 in. (30 cm) for appliances greater
	than 50,000 btuh (15 Kw) to a non mechanical air supply inlet
	into building or combustion air inlet to another appliance
AREA WHERE TERMINAL IS NOT PERMITTED

1.Permitted only if veranda, porch, deck or balcony is fully opened on a minimum of two sides beneath the floor.

2.A vent shall not terminate above a sidewalk or paved driveway that is located between two single family dwellings and serves both dwellings.

FIGURE 11

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