GE PGP990DENBB Owner's Manual & Installation Instructions page 24

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Make a sketch of the total system. Identify the
type of each fitting and the length of straight
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.
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• Ducting must conform to local code materials.
• Save for local electrical inspector's
use.
• Use galvanized or aluminum duct in 6" round or
3 " x 10" size, or a combination of both.
1 4
• 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.
Through cabinet toe space
• 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.
Air flow
Between floor joist
Duct tape over seam
and screw
Screw
• Ducting a cooktop is easy but critical for proper
performance.
• After reading these instructions, plan the duct run.
• Install the duct hardware.
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.
The number of downstream elbows or transitions
should be limited to three.
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.
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.
High altitude installations: It is advisable to reduce
allowable duct run by 20%.
Follow the duct calculation in this manual carefully
for best performance and satisfaction.
be installed with a ventilation system that blows
air downward toward the range. Using this type of
ventilation system may cause ignition and combustion
problems with the gas cooking appliance resulting in
personal injury or unintended operation.
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The appliance shall not