Installation Instructions
INSTALL THE DUCTWORK
• Ducting must conform to local code materials.
• IMPORTANT: Save for local electrical inspector’s
use.
• Use galvanized or aluminum duct in 6
″
round
or 3
1
⁄
4
″
x 10
″
size, or a combination of both.
•
NOTE: Local building codes must be followed
in specifying approved type and schedule of
ALL duct used.
• Always use an appropriate roof or wall cap with
damper.
• Laundry type wall caps should NEVER be used.
• Install ductwork, making male-female
connections in the direction of airflow as shown.
Secure all joints with sheet metal screws and duct
tape to assure an airtight seal.
• Use the shortest and straightest duct run
possible. For satisfactory performance, the duct
run should not exceed 100 feet equivalent length.
• Use the Duct Length Chart on page 25 to find
the equivalent length of the run.
• Ducting a cooktop is easy but critical for proper
performance.
• After reading these instructions, plan the duct run.
• Install the duct hardware.
GENERAL CONSIDERATIONS:
1. Use quality metal duct of at least 26-gauge
galvanized or 24-gauge aluminum. Inferior quality
pipe and fittings can cause up to twice the restriction
shown and are a poor value. See the Prepare for
DuctWork section of this manual for optional
under-slab ducting. Local codes may require
a heavier gauge material or restrict PVC.
2. Distance between adjacent fittings (elbows,
transitions, etc.) should be at least 18
″
.
The farther the better. Closer distance
promotes turbulence which reduces airflow.
3. The number of downstream elbows or transitions
should be limited to three.
4. Handmade crimps are likely to cause restrictions.
5. If an alternate wall or roof cap is used, be
certain duct size is not reduced and that there
is a backdraft damper. It is best to use listed caps
to be certain of proper performance.
6. Thermal breaks: In areas of extreme cold weather,
it may be necessary to provide a short length
of nonmetallic duct as close to the wall as possible
to prevent conduction along the metal duct.
7. High altitude installations: It is advisable to reduce
allowable duct run by 20%.
8. Follow the duct calculation in this manual carefully
for best performance and satisfaction.
PLAN THE DUCT RUN
1. Make a sketch of the total system. Identify
the type of each fitting and the length of straight
pipe. Refer to the examples on page 25.
2. Enter your run into the Duct Length Chart on
page 25. Elbows, wall caps and other fittings are
shown in the chart with their equivalent straight
duct length. Each fitting value must be added
to the amount of straight duct length used to
determine the overall straight duct equivalent
length. Use the following examples as a guide.
3. Using good quality ducting material, install per
these instructions. A few minutes and pennies
spent now will pay long term dividends for
the life of the cooktop.
8
9
Through cabinet toe space
Between floor joist
Downward venting
Duct tape over seam
and screw
Air flow
Screw
24
PREPARATION
