Ducting Advice

Getting it right the first time!

There are still occasions where our rangehoods are installed with incorrect ducting e.g. flexible ducting, and consequently the rangehood does not perform well. Reducing the size of the ducting can have detrimental effects on airflow and the overall performance of the rangehood.

Changing the ducting can be a costly and a stressful exercise, particularly when joinery needs to be removed or altered. We have an extensive ducting range, from rectangular, square and round ducting, to assist with individual ducting situations and or preferences. All ducting pieces are CAD-designed to our specifications and are manufactured in standard Zincalume, which is solid metal.

The size of the ducting will be determined by the number of motors per rangehood.

We submit the following for consideration:

	Airflow on high speed m3/hr
Unobstructed Qasair motor ( bench test )	980
Qasair motor with 200mm diameter outlet	885
Qasair motor with 150mm diameter outlet	673
Qasair motor with 90mm diameter outlet	290

Tests are done at the Condari factory with a Beacon Anemometer Air Flow Meter and are generally considered to be accurate to ±10%. As the table illustrates, reducing the size of the ducting from 200mm to 90mm results in a massive 67% drop in air flow.

Condari therefore recommends DO NOT REDUCE THE SIZE OF THE DUCTING.

All stainless steel ducting is manufactured in type 445M2, which is more resistant to corrosion. This is due to a higher content of chromium at 22% and 1% molybdenum.

Ducting can also be custom-made in Dulux Colorbond steel or custom-made in a Dulux Powder Coatings finish.

Condari also manufactures custom-made ducting for tricky situations. For further information about custom-made ducting, please contact a QASAIR representative from your state, contact details can be found on our contacts page Find Your Nearest Contact. Detailed information will be required for our team to help specify correctly and to be able to manufacture ducting that will suit your requirements.

Tips to correctly duct your rangehood:

Always use the correct size ducting – DO NOT reduce the size of the ducting.

Always use solid metal ducting, to our specifications.

Always duct to the outside atmosphere, using the shortest duct run possible or suitable for the number of motors inside your rangehood.

Do not duct into the ceiling space.

Do not use flexible ducting.

Avoid sharp 90 degree bends as much as possible, use 45 degree bends instead wherever possible.

Use our cylindrical ducting whenever possible.