7
Venting Requirements
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Vent system must terminate to the outdoors.
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Do not terminate the vent system in an attic or other enclosed
area.
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Do not use 4" (10.2 cm) laundry-type wall caps.
■
Use metal vent only. Rigid metal vent is recommended.
Plastic or metal foil vent is not recommended.
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The length of vent system and number of elbows should be
kept to a minimum to provide efficient performance.
For the most efficient and quiet operation:
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Use no more than three 90° elbows.
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Make sure there is a minimum of 24" (61.0 cm) of straight
vent between the elbows if more than 1 elbow is used.
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Do not install 2 elbows together.
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Use clamps to seal all joints in the vent system.
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The vent system must have a damper. If the roof or wall cap
has a damper, do not use the damper supplied with the range
hood.
■
Use caulking to seal exterior wall or roof opening around the
cap.
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The size of the vent should be uniform.
Cold weather installations
An additional back draft damper should be installed to minimize
backward cold air flow and a thermal break should be installed to
minimize conduction of outside temperatures as part of the vent
system. The damper should be on the cold air side of the thermal
break.
The break should be as close as possible to where the vent
system enters the heated portion of the house.
Makeup air
Local building codes may require the use of makeup air systems
when using ventilation systems greater than specified CFM of air
movement. The specified CFM varies from locale to locale.
Consult your HVAC professional for specific requirements in your
area.
Venting Methods
A 10" (25.4 cm) round vent system is needed for installation (not
included). The hood exhaust opening is 10" (25.4 cm) round.
NOTE:
Flexible vent is not recommended. Flexible vent creates
back pressure and air turbulence that greatly reduce
performance.
Vent system can terminate either through the roof or wall.
Calculating Vent System Length
To calculate the length of the system you need, add the
equivalent feet (meters) for each vent piece used in the system.
The maximum equivalent vent lengths are:
10" (25.4 cm) round vents - 60 ft (18.3 m)
Example vent system
The following example falls within the maximum recommended
vent length.
Roof Venting
Wall Venting
A. Roof cap
B. 10" (25.4 cm) round vent
A. Wall cap
B. 10" (25.4 cm) round vent
A
A
B*
B*
Vent Piece
Equivalent Length
45° elbow
2.5 ft
(0.8 m)
90° elbow
5.0 ft
(1.5 m)
1 - 90° elbow
= 5.0 ft (1.5 m)
1 - wall cap
= 0.0 ft (0.0 m)
8 ft (2.4 m) straight
= 8.0 ft (2.4 m)
Length of system
= 13.0 ft (3.9 m)
90 elbow
6 ft (1.8 m)
2 ft
(0.6 m)
Wall cap