GE ZV900 installation instructions Duct Fittings, Flexible ducting, Installation Preparation

Installation Preparation

DUCT FITTINGS

Use this chart to compute maximum permissible lengths for duct runs to outdoors.

NOTE: Do not exceed maximum permissible equivalent lengths!

Maximum duct length: 100 foot for 8″ round duct

Flexible ducting:

If flexible metal ducting is used, all the equivalent feet values in the table should be doubled.

The flexible metal duct should be straight and smooth and extended as much as possible.

DO NOT use flexible plastic ducting.

NOTE: Any home ventilation system, such as a ventilation hood, may interrupt the proper flow of combustion air and exhaust required by fireplaces, gas furnaces, gas water heaters and other naturally vented systems. To minimize the chance of interruption of such naturally vented systems, follow the heating equipment manufacturer’s guidelines and safety standards such as those published by NFPA and ASHRAE.

This Hood Must Use an

8″ Round Duct.

				Total
		Equivalent	Quantity	Equivalent
Duct Piece	Dimensions	Length*	Used	Length
	Round,	1 ft.
	straight	(per foot
		length)
	3-1/4″x 12″	1 ft.
	3-1/4″x 24″	(per foot
	straight	length)
	8″ round
	90° elbow	15 ft.
	8″ round
	45° elbow	8 ft.
	3-1⁄4″x 12″
	90° elbow	11 ft.
	3-1/4″x 12″ or
	45° elbow	6 ft.
	3-1/4″x 12″
	90° flat elbow	24 ft.
	8″ round to
	3-1/4″x 12″
	or 3-1/4″x 24″ transition	1 ft.
	3-1/4″x 12″ to 8″
	round transition	8 ft.
	8″ round
	to 3-1/4″x 12″ or
	transition 90° elbow	16 ft.
	3-1/4″x 12″ to 8″ round
	round transition 90° elbow	17 ft.
	8″ round
	wall cap
	with damper	30 ft.
	3-1/4″x 12″ wall cap
	with damper	30 ft.
	8″ round
	roof cap	26 ft.
	8″ round
	roof vent	26 ft.

*Actual length of straight duct plus duct fitting equivalent. Equivalent length of duct pieces are

based on actual tests conducted by GE Evaluation Total Duct Run Engineering and reflect requirements for good

venting performance with any ventilation hood.

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