DIRB65 Genuine Deflecto Duct Increaser Reducer 125mm to 150mm Aluminium, Universal Rangehood and Exhaust Duct Fitting

Joining 125mm ducting to 150mm? Deflecto DIRB65 is an aluminium increaser and reducer that steps between the two sizes, so it works in either direction. It's handy when a rangehood spigot and the existing duct don't match, or when you're upgrading a run to a larger diameter. As a universal fitting there's no model list to check, just confirm the sizes of the spigot and duct you're joining.

Matching rangehood and duct sizes

Rangehoods and exhaust fans move air best when the duct is the right size and the joints are smooth and sealed. Many hoods have a 150mm outlet while older ceilings or walls may already have 125mm duct, or the reverse. Forcing a mismatched duct on leaves gaps that leak greasy air into the ceiling space, and squashing it narrows the airflow. A proper increaser reducer makes a tidy transition. Keep in mind that stepping down to a smaller duct can reduce the hood's extraction and raise the noise, so check your hood's recommended duct size.

Part details

• Deflecto part DIRB65
• Steps between 125mm and 150mm duct
• Aluminium construction
• Works as an increaser or a reducer
• Universal fitting for rangehood and exhaust ducting

Installing the increaser reducer

Turn the rangehood or fan off at the wall before working on the ducting. Push each end over or into the matching duct or spigot, then secure every joint with duct clamps or screws and seal it with aluminium foil tape so grease and moisture can't escape. Keep the run as short and straight as possible. Any new wiring for a rangehood must be done by a licensed electrician.

Questions about this part

Which way round does it go?

Either way. The narrow end takes 125mm and the wide end takes 150mm, so you can go up or down in size depending on which side the hood or fan is on. Seal both joints with foil tape once it's in place.