Added turning vanes to the worst possible elbow ever

[skeer]

According to my j-calcs this elbow I have was worth like 110'. This weekend I added some diy turning vanes to it, 4 of them. I can no way to measure any changes but it's gotta be better.

I don't have a ready pic of it re-assembled but you can use the green paint to see, there was a rectangular duct (long side against the wall) with a sweeping 90* to this horizontal trunk.

 

[danski0224]

That turning vane install looks bad.

Adding them improperly is worse than leaving it alone.

You should be using commercially available vane rail, and you can make single thickness vanes about 6" wide to fill the slots to length.

Or commercially available double wall vanes.

Static pressure testing before and after should tell the tale. Or measuring airflow in the same location before and after.

 

[skeer]

Well I'm not a pro so.. And yeah, lots of things when done improperly are worse than before however even though they aren't perfect, my angles were rolled and the edges point where they are supposed to.

 

[fitter30]

Just put curve piece of metal covering the heel of the ell. Like a sweep ell.

 

[danski0224]

Just put curve piece of metal covering the heel of the ell. Like a sweep ell.

Waste of time.

The restriction is from the throat of the elbow, not the heel.

 

[readhead]

You didn’t say what the problem was that led you to this “solution”. What ever it was it is worse now. There is no elbow. It’s a joint of duct that is capped and then some crude S&Drive work to attach another piece of duct. Turning vanes are actually pretty technical. Having made up and installed hundreds of them for commercial work.

 

[Jackfre]

Ah, a disagreement between two of our experienced guys. Danski is correct that the problem is the bend, but you solve these things either the right way or you sneak up on it. Anything you do here is the old lipstick on a pig with that fitting, but without other major work, I’m with Fitter. What I would suggest is to get your hands on a manometer and a few feet prior to the fitting see what the reading is. Don’t take the reading right next to the ell. To much turbulence.
In looking at the picture again you have a poorly built 90 going to an adjustable 90 off the top. If you really want to improve the air flow ditch the line off the top, install vertical turning vanes throwing the air off to the side and do a proper transition to the round. Avoid back to back fittings. Yes you loose some space in the basement but you will get air flow where you need it. No duct seal on that ell as it sits now and I’ll bet the joint leaks like crazy. The manometer will let you see what is happening. Curious what the temp drop is from the furnace supply to the outlet too. you might consider wrapping insulation on the duct. Insulation and duct seal after the fact is just a ***** of a job, but it works.

 

[danski0224]

As someone mentioned earlier, it isn't even a fitting, it's a cap and tap between two pieces of duct.

It *could* be fixed with a proper fitting...

Shops put a radius on the heel because it's less metal, not because it works better.

 

[brewchief]

As someone mentioned earlier, it isn't even a fitting, it's a cap and tap between two pieces of duct.

It *could* be fixed with a proper fitting...

Shops put a radius on the heel because it's less metal, not because it works better.

I think your 100% wrong, shops put a radius on the heel because it looks like it flows more, you put the radius in the throat and square the heel and it looks wrong even though it's better.

 

[turbowoodworker]

I wish I knew what they were talking about

 

[readhead]

I detailed duct fittings for several years way back in my union sheet metal career. A radius heal maintains the aspect ratio which reduces static pressure.

A radius heal certainly saves metal but increases labor. You will spend more time working the locks. If it is lined it will take longer to cut and more waste.