Owner's Manual

Brands

Best Practices

Venting Installation Instructions for

Range Hoods and Wood Hood Liners

(All Models)

—Addendum to Installation Instructions—

IMPORTANT: Problems caused by improper installations are not covered by the manufacturer’s warranty.

IMPORTANT: Undersized and improperly installed duct pipe and/or other ventilation components will cause

excessive static pressure (air resistance), that may result in rattling, vibration and air buffeting noises, as well as

inadequate ventilation.

1. Building Codes - Kitchen Hood Ventilators should be installed by qualified technicians familiar

with state and local building codes.

2. Duct Pipe and Fittings (Elbows, Transitions, Roof & Wall Caps)

a. Use round or rectangular rigid metal duct only. Where possible, use round duct as it creates the least

amount of static pressure. DO NOT use flex duct.

b. All duct sections and fittings (EXCEPT DAMPERS, per Section 4), should overlap and be connected with

at least 3 – 4 equally spaced screws and wrapped tightly with 2 – 3 layers of Aluminum Foil Metal Duct

Tape. This type of duct tape is more durable than traditional cloth duct tape. DO NOT use butt joints.

c. For best air flow, elbows and pipe size transition fittings should not be directly connected to one

another. Where possible, always include at least 15 inches of straight pipe between fittings.

3. Duct Pipe and Fitting Sizes. (See Duct Sizing Chart and Area Calculations Section for more detail)

IMPORTANT: DO NOT use either of the following duct pipe sizes or fitting sizes for any kitchen hood

ventilator installations:

- 6” round duct pipe

- 3.25” x 10” rectangular x 6” round transitions

- 6” x 7” linear transitions

IMPORTANT: No portion of any length of duct pipe or fitting should be smaller than the discharge port of the

ventilator. This is very important because any type of restriction anywhere in the ventilation system will

cause increased static pressure (air resistance), that may result in rattling, vibration and air buffeting noises,

as well as inadequate ventilation.

Example: For ventilator models with 3.25” x 10” discharge ports, no part of the roof cap or wall cap’s air path

should be smaller than 3.25” x 10” (32.5 square inches) or 7” round (38.5 square inches). See Roof Caps and

Wall Caps section for more detail.

Exception: For some short duct runs inside walls framed with 2 x 4 studs, it is a common industry practice to

transition a 7” round duct to a 3.25” x 10” rectangular duct. If space allows, it is best to use a 3.25” x 14”

rectangular duct with a 3.25” x 14” x 7” transition.