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Griff
2006-07-11, 02:46 PM
Any idea why when I size the primary ductwork in the tutorial (Sizing the Duct: Velocity Method) I get the duct reducing size and then enlarging after that. I was wondering if it is a setting within the elbow fittings?

Griff
2006-07-11, 04:37 PM
I thought I ought to mention, that I have kept the same file for all the Mechanical tutorials instead of opening each new dataset for each individual tutorial. I was doing this so I could follow along and find any problems.

I mention this because I just opened the dataset for the 'Duct Sizing - Velocity and it sized correctly. I've tried following the tutorial closely so I can learn how the program works, so I'm confused why my file is different than the dataset file. I also noticed on my file that when I highlight and check the properties of what would be the largest duct size on the right primary duct there is no listings for the flow, velocity... On the next section further toward the endcap there is a listing for flow, velocity... So, I've done something wrong in the tutorial, but I don't know where. If anyone has any idea what would cause this problem I'd appreciate letting me know, so if it comes up again I know how to fix it. Thanks for any input.

Griff
2006-07-11, 08:09 PM
First of all before I go much further, has anyone completed the Mechanical tutorial "Creating Air Systems" then placed a round duct endcap on the end of the primary ducts, resized the primary ductwork using the velocity method as they suggest at 2500 FPM and had the ductwork size correctly?

I am still working on this issue and have determined a few more things.

If you open the 'i routing solutions.rvt' dataset file and highlight (2 tabs) the left primary system up to the VAV's, you will notice that it looks just like my file, messed up. But then I realized that I didn't put a round duct endcap on the one end of the primary duct to establish flow direction. So when I did that and sized it, the ductwork looked correct.

So, then I figured I must have some end of the ductwork (other than the main that will be connected to the rooftop unit) that is not connected as it should be. I first removed the round duct endcap and reinstalled it, making sure that it was connected (connection snap). I resized the system again but still no go. I then looked at my 3d view and noticed that I had the 8" round duct disconnected from the VAV above office 3. I connected it and figured that would fix the problem, but still it size correctly.

Any suggestions?