Ducting Do's And Don'ts - hestan KVI36TQ Manuel D'installation, D'utilisation Et D'entretien

DUCTING DO'S AND DON'TS

GENERAL REQUIREMENTS GENERAL REQUIREMENTS
Observe local codes regarding special duct requirements and placement of duct work against
EN
combustibles.
• Using recommended transitions (included) will ensure proper efficiency.
• Using recommended roof caps or wall louvers (see VENT ACCESSORIES) will ensure proper
efficiency.
• Use foil HVAC tape (not grey cloth duct tape) to seal all joints.
• The hood must be ducted to the outdoors without restrictions.
BLOWER REQUIREMENTS BLOWER REQUIREMENTS
The island dual blower unit (T200 = 550 CFM) used in 36" and 42" systems, outputs through the
included transition to 8" round duct or equivalent. (50 sq. inches)
The 54" system uses a cluster of four blowers (T400 = 1100 CFM) which output through the
included transition to 12" round duct or equivalent. (113 sq. inches)
DUCTING REQUIREMENTS (DO'S AND DON'TS) DUCTING REQUIREMENTS (DO'S AND DON'TS)
• NEVER reduce the duct size. When combining ducts together, the square inch area of
the outlet duct must be equal or greater than the total square inch area of the ducts being
combined.
• Only use smooth galvanized metal duct. Do not use flexible or corrugated duct. This type of
duct will restrict airflow and reduce performance.
• Make the duct run as short and as straight as possible with as few turns as possible.
• Avoid sharp-angled turns. Instead, use smooth, gradual turns such as adjustable elbows or 45
degree angled turns.
• For duct runs over 20 feet, increase the duct diameter by one inch for every ten feet of duct.
• When planning length, a 90 degree elbow is equivalent to 5 feet of duct.
TERMINATION REQUIREMENTS TERMINATION REQUIREMENTS
Airflow must not be restricted at the end of the duct run.
A wall louver or roof cap is required for each duct run.
Every wall louver or roof cap must include a gravity damper to prevent back drafts.
Do not use screen wire or spring-loaded doors on wall louvers or roof caps.
Do not terminate venting into an attic or chimney.
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©2020 Hestan Commercial Corporation
YES
Smooth duct Smooth gradual turn
NO
Flexible duct Sharp angled turns
Proper combining
of two ducts
Improper combining
of two ducts