Greenheck Fan 470656 manual Installation of Standard Indoor Venting, Vent Pipe Diameter

Installation of Standard Indoor Venting

Standard Indoor Venting uses one penetration through an exterior wall or roof for venting the flue exhaust. The combustion air is supplied from the air inside the building. Units must not be installed in a potentially explosive, flammable, or corrosive atmosphere. To prevent premature heat exchanger failure, do not locate unit where chlorinated, halogenated or acid vapors are present.

When units are installed in tightly sealed buildings, provisions should be made to supply an adequate amount of infiltration air from the outside. The rule of thumb is that an opening of one square inch should be provided for every 1000 BTUs per hour of input rating.

Vent terminals must be used. Construct the vent system as shown in the drawings. Reference the Vent Pipe Diameter table and Exhaust Vent Pipe table for additional details.

				Exterior
A = 12 inch minimum
					Wall
	Pitch vent pipe
	downward
	from furnace
	¼ inch per foot		A
		EXHAUST
		Air Inlet
				Exhaust
				Vent
				Terminal

Standard Indoor Venting - Horizontal

Vent Pipe Diameter

Select the vent pipe diameter. Use only the specified pipe diameter.

Furnace Size	Exhaust Pipe Diameter
(MBH)	(inches)
75 - 175	4
200 - 400	6

Installing Exhaust Vent Pipe

Install the vent pipe with a minimum downward slope (from the unit) of 1/4-inch per foot (horizontal venting only). Securely suspend the pipe from overhead structures at points no greater than 3 feet apart.

The minimum vent length is 5 feet for horizontal and 10 feet for vertical. The maximum vent length is 70 feet. The total equivalent vent length must include elbows. The equivalent length of a 4 inch elbow is 6 feet and the equivalent length of a 6 inch elbow is 10 feet. Attach the vent terminal to the end of the exhaust pipe.

Vent	Minimum	Maximum
Length	(feet)	(feet)
Horizontal	5	70
Vertical	10	70

A = 12 inch minimum

B = 12 inch minimum, but should size according to expected snow depth

B

Roof Line

EXHAUST

A

Exhaust Vent

Terminal

Air Inlet

Standard Indoor Venting - Vertical

®

Model IG / IGX Make-Up Air 9