flex duct turns

08-25-2010, 09:53 AM	#1
sjthompson Member   Join Date: Aug 2010 Posts: 42	flex duct turns Should I have solid 90"S and 45's at the bends in my flex duct off the distribution box, and in the ceiling registers?

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08-27-2010, 08:22 PM	#2
MI-Roger Member   Join Date: Aug 2009 Posts: 133	flex duct turns Although not absolutely necessary, I would recommend it. I have seen too many installations where the flex duct has nearly collapsed into itself on bends. A hard elbow is clearly better.

08-27-2010, 09:40 PM	#3
beenthere An old Tradesmen   Join Date: Oct 2008 Location: PA Posts: 18,662	flex duct turns Care must be taken not to kink the flex when making turns/bends. If you really want to use hard pipe ells, nothing wrong with that.

08-27-2010, 10:20 PM	#4
Red Squirrel Wire Chewer     Join Date: Jun 2009 Location: Ontario, Canada Posts: 2,961	flex duct turns I would avoid flex where you can, in permanent setups. Think of how much more dust they will collect over time due to how they are made.

08-28-2010, 06:58 AM	#5
COLDIRON Member   Join Date: Mar 2010 Location: PENNSYLVANIA Posts: 1,902	flex duct turns If you are making bends or connecting flex to register boots make sure you use a wide radius when making the turns and support them if needed. No sharp bends.

08-28-2010, 07:40 PM	#6
sjthompson Member   Join Date: Aug 2010 Posts: 42	flex duct turns so how much diffrence does it make how tight the turn is into the register box? All mine are laying on the insulation on the attic floor and the just 90 down into the register box.

08-28-2010, 09:02 PM	#7
beenthere An old Tradesmen   Join Date: Oct 2008 Location: PA Posts: 18,662	flex duct turns The tighter the 90, the more restricted the air flow is. Hop in your car. Drive around the block. The first 2 turns, make them wide. Make the next 2 turns very tight. Feel the difference. It has the same effect on air. Throws more air to the one side, and slows it down.

08-28-2010, 10:27 PM	#8
Gary in WA Moderator   Join Date: Mar 2009 Posts: 8,780	flex duct turns I would. You should be one size bigger on the straight runs: http://rockwallcontrols.com/Resident...ag=air-ducting Pressure losses: http://www.mmmfg.com/pdfs/True_Cost_...x_10-27-06.pdf http://www.thefreelibrary.com/Pressu.....-a0201591046 Gary __________________ Clothes taking longer to dry? Clean the dryer screen in HOT water if using fabric softener sheets. They leave a residue that impedes air-flow, costing you money. Clean the ducting in the last six months? 17,000 dryer fires annually!