DH
Document # | Revised 07/03/13 Page 2/2 | |
| Distinctive 30 and 36” Wide | PLANNING |
| Wall Mount Range Hood | GUIDE |
Planning the Duct Work
■■ For optimal performance, consult a qualified HVAC specialist when designing the duct system.
■■ All duct work materials (including screws and duct tape) must be purchased separately by the customer.
■■ When planning new duct work, always look for the shortest, most direct route to the outside.
elbow (notincluded)| fan | fan |
■■ You may increase the duct size over the duct run if desired. To prevent a back draft, never decrease the duct size over the run. If existing duct work is smaller than 8 inches, remove and replace with
■■ To prevent
Duct Work Design Tips
■■ Wherever possible, reduce the number of transitions and turns to as few sharp angles as possible. Two staggered 45° angles are better than one 90°.
■■ Keep turns as far away from the hood exhaust as possible, and as much space between bends as possible.
■■ For best performance, use round duct instead of rectangular, especially when elbows are required.
■■ If multiple elbows are used, try to keep a minimum of 24” straight duct between them. Avoid “S” or “back to back” use of adjacent elbows.
■■ In regions where the weather gets extremely cold, use thermal breaks, such as a short section of
■■ Do not use duct work that is smaller in
Calculating the Maximum Duct Run Length
The maximum straight duct length for the hood is determined by the type of duct used. See the chart below.
| Duct Size | Maximum Straight | |
| Duct Run | ||
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| 8” round | 60 feet | |
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| 10” round | 50 feet | |
| 3¼” X 10” rectangular | 50 feet |
For each elbow and transition added to the duct work, a certain number of feet must be subtracted from the maximum duct run to compensate for wind resistance. To determine the length the duct work cannot exceed, subtract all of the equivalent lengths of the elbows and transitions listed below from the maximum duct run above.
Duct Work Equivalent Lengths
Equivalent Number of Feet -Duct Elbows and Transitions| 45° elbow, 8 inch | 3 feet | 3 ¼” X 10”, 45° elbow | 7 feet | |
45° elbow, 10 inch | 2 feet | 3 ¼” X 10”, 90° elbow | 15 feet | |
90° elbow, 8 inch | 7 feet | 3 ¼” X 10”, 90° flat elbow | 20 feet | |
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90° elbow, 10 inch | 5 feet | 3 ¼” X 10” to 8” round | 4 feet | |
transition | ||||
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90° 3 ¼” X 10” to | 25 feet | 3 ¼” X 10” to 10” round | 4 feet | |
8” round transition | transition | |||
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Roof cap | * | Wall cap** | * |
*The equivalent lengths of roof and wall caps vary with model and configuration. For equivalent length, contact the manufacturer or a qualified HVAC specialist.
All specifications subject to change without notice. | www.dacor.com | Phone: (800) |