Piping System - Flow Section is 0 [help!]

This is my very first thread and I've been using AUGI for all my REVIT needs these last few weeks. This time it is dire! But it may be simple for a lot of you. By the way I'm usinge Revit MEP 2013

If you look at my attached screenshot, I've piped my chiller to Revit standard pump for the CWS and my CWS piped to the Cooling Tower (also offered by Revit). Then I piped the CWR back to the chiller. (This is only a test model)

When I select pipe sizing for the CWR, Revit has sized my piping; however, when I size my CWS (which are connected to the pumps), I receive an error: "Sizing failed. Flow for section is 0".

I don't think your suppose to add the pumps to the CWS/R system hierarchy. Although when I connect to the pumps, the pump has automatically made its own system, default to "Hydronic Supply 1"

Has anyone used the Revit pump: Based mounted? And why is the flow section 0. Am I to change any connector features in the pump family?

What is the deal here?

Hard to tell without getting into the project file, but I would guess that it is because you have a loop where the pumps are. Revit will calculate the flow down the pipe, and when it gets to the tee it will go one way and see what happens, in the case of a branch joining into a main this is ok when it figures out the correct direction. (correct direction is governed by the flow direction of the commectors in the families).

However in your model the flow can get caught in a loop due to the way that it has been simplified by Revit (take a look at a tee or an elbow family, there are no directions specified, however you could change the connectors from fittings to CWS In or Out but that is too much work)

Basically as soon as you give Revit 2 options it gives up and goes home. You can either make a whole bunch of fittings with the direction setup (havent tested in this instance) or you will need to model the 2 pumps as 1 piece of mechanical equipment.

Drew,
I never thought about configuring the fitting themselves to determine the direction of flow. My focus was purely on the equipment.

I'll have to give that a shot. I did, however, set the pumps as system with flow factor @ 50%. This partially solved some issues with flow being 0. However, I'm back to the same issue for the exhaust fan system with flow mismatch.

Can you clarify what you mean by modeling the 2 pumps as a single mech equipment. How is this possible? Through setting up in system browser?

Quote:

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Originally Posted by persaudchris358036

Hey, I've uploaded my project test file which includes the main central plant cooling equipment. Hopefully it can be troubleshooted. Thanks!!!

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The upload didn't stick...

Yeah I realized that my file is too big. I'm not sure how to reduce the size other than zipping it. Also I think we're allowed a 10mb quota. I'm not sure if its for this post only or overall as a AUGI member

Quote:

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Originally Posted by persaudchris358036

Can you clarify what you mean by modeling the 2 pumps as a single mech equipment. How is this possible? Through setting up in system browser?

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See the attached, I nested the pumps into a new mech equipment family, added some pipe (extrusions and sweeps) and connectors. The flow works through the new equipment, and you could make it more parametric with a little more effort than I put in!

Does that work for your requirements?

This definitely does work. Since you've nested the pumps add piping, the pipes do not change in size only independents connecting to its dependents. I was about to model the same way as individual pumps and its works the same way. Although I just get a sizing error being that pipes are big. If I modeled a 100 gpm flow I'd expect about 4 FPS and 2ft/100ft pipe friction which should equate to a 3" dia pipe. This is not so. Does Revit calculate incorrectly pipe sizes?

Btw, how your you able to get the file so small?. Even with the same number of equipment my file size is double yours.

Quote:

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Originally Posted by persaudchris358036

Yeah I realized that my file is too big. I'm not sure how to reduce the size other than zipping it. Also I think we're allowed a 10mb quota. I'm not sure if its for this post only or overall as a AUGI member

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Here is my favorite method for sharing large files...Dropbox

Here is a good set of info from an AU class (I found it from a simple google, so I think sharing it is OK). To give credit, this is the author details:

Getting into the Flow: Understanding Connectors in Revit MEP Content
Martin Schmid, P.E. – Autodesk
ME204‐3

I actually do use Dropbox. It's pretty good, not certainly not very good with over 100mb files