Installation Instruction

5
For Best Performance:
■ Use 26-gauge minimum galvanized or 25-gauge minimum
aluminum metal vent. Poor quality pipe fittings can reduce
airflow. Flexible metal vent is not recommended.
NOTE: Local codes may require a heavier gauge material.
■ Metal duct may be reduced to 30-gauge galvanized steel
or 26-gauge aluminized steel if allowed by local codes.
This reduction is based on information in the International
Residential Codes Section M1601.1 (2006 edition).
■ Do not install 2 elbows together.
■ Use no more than three 90° elbows.
■ If an elbow is used, install it as far away as possible from
the vent motor exhaust opening.
■ Make sure there is a minimum of 18" (45.7 cm) of straight
vent between the elbows if more than one elbow is used.
■ Elbows too close together can cause excess turbulence that
reduces airflow.
■ Do not use a 5" (12.7 cm) elbow in a 6" (15.2 cm) or 3
1
/
4
" x 10"
(8.3 cm x 25.4 cm) system.
■ Do not reduce to a 5" (12.7 cm) system after using
6" (15.2 cm) or 3
1
/
4
" x 10" (8.3 cm x 25.4 cm) fittings.
■ Avoid forming handmade crimps. Handmade crimps may
restrict airflow.
■ Use a vent cap for proper performance. If an alternate wall
or roof cap is used, be certain the cap size is not reduced
and that it has a backdraft damper.
■ Use vent clamps to seal all joints in the vent system.
■ Use caulking to seal exterior wall or roof opening around
the cap.
The length of vent system and number of elbows should be kept
to a minimum to provide efficient performance.
The maximum equivalent length of the vent system is 60 ft
(18.3 m). For altitudes above 4,500 ft (1372 m), reduce
recommended vent run by 20% for best performance.
Cold Weather Installations
An additional backdraft damper should be installed to minimize
backward cold air flow.
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
Common venting methods are shown for a counter-mounted
downdraft cooktop. The cooktop may be vented through the
wall or floor.
Option 1 - Roof Venting Option 2 - Wall Venting
A
B
A
B
A. 6" (15.2 cm) round roof venting
B. Roof cap
A. 6" (15.2 cm) round wall venting
B. Wall cap
Option 3 - Venting
Between Floor Joist
Option 4 - Venting Behind
Cabinet Kick Plate
A
B
A B
3¼" x 10"
(8.3 cm x 25.4 cm)
A. Wall cap
B. 6" (15.2 cm) round wall venting
A. Wall cap
B. 6" (15.2 cm) round wall venting