RevitCity.com Logo

Home  |  Forums  |  Downloads  |  Gallery  |  News & Articles  |  Resources  |  Jobs  |  FAQ  |  SearchSearch  |  Join  |  LoginLogin

Welcome !

60 Users Online (59 Members): Show Users Online - Most ever was 626 - Mon, Jan 12, 2015 at 2:00:17 PM

 

Forums

Forums >> Revit Systems >> Technical Support >> AIR FLOW GOING THE WRONG WAY

Search this ThreadSearch this Thread | Page 1 of 1 |

Fri, May 23, 2014 at 9:12:41 PM | AIR FLOW GOING THE WRONG WAY

#1

dbruckman


active

Joined: Tue, May 20, 2014
0 Posts
No Rating


I've been in Revit Architectural for years, but am just now starting to use the MEP. 

This is Revit 2015

I have set up a make up air supply system in a building, set terminals, a supply air unit, connected the whole thing up with ductwork and what I get is the total supply CFM showing at the opposite end of the systme, at the cap at the end of the line, and zero CFM at the unit outlet.  The flow is exactly opposite of what it should be.

 

What am I doing wrong?


This user is offline

 

Sat, May 24, 2014 at 7:03:42 PM | AIR FLOW GOING THE WRONG WAY

#2

dbruckman


active

Joined: Tue, May 20, 2014
0 Posts
No Rating


I've been horsing with this for a bit, and it seems as though the sequence in which you add elements to a system is crucial to the system being able to collect data on air flow.  If you begin with an air terminal you appear to need to go all the way back to the supply unit rather than then setting duct from the air handler to that terminal.   I THINK...... or if you are adding duct from an air handler, you need to add the air terminal last. It seems to go haywire if you try to do it in parts along a run, but not in a sequence.

 

Still messing with it, though...not sure I get it yet.


This user is offline

 

Wed, Jun 4, 2014 at 12:01:12 PM | AIR FLOW GOING THE WRONG WAY

#3

Gyvven


active

Joined: Wed, Dec 19, 2007
69 Posts
5 Stars: 2 Votes


Airflow populates from the air terminal back to the mech equipment. You must define your CFM at the air terminal and it will automatically sum at the VAV or whatever equipment your hooking up to. Order of connection doesn't have anything to do with it in my experience.

The output on your equipment should be set to Calculated (with Flow linked to a parameter), the input on the air terminal should be Preset (with Flow linked to a parameter). The inlet on your equipment, if you're dealing with a VAV, should be set to Preset (with Flow linked to the same parameter as the outlet). This allows the eqipment to see the "demand" from the air terminals and feed that information further up the chain, all the way back to the AHU. (I made an autosizing VAV and Air Terminal that are in the downloads section, but I need to update them since I've made some nifty changes recently.)

Using the duct inspector, or even applying a System Color Scheme to the view, will show you the air flow at every point along the duct. The airflow at a cap and it's adjacent ductwork should always be zero, unless somebody is messing with you and turned your duct cap into an air terminal. Don't laugh, I've seen it happen.... ok, I did it.

 

I hope this helps, unless I completely missed the issue. If I did, upload your model and we can take a look at it and see what's happening. I won't be able to since I'm not on 2015 yet.

 

-Gyv


This user is offline

 

Search this ThreadSearch this Thread | Page 1 of 1 |



Similar Threads

Thread/Thread Starter

Forum

Last Post

Replies

HELP with air terminals

Revit Systems >> Technical Support

Tue, Oct 25, 2011 at 9:44:46 AM

13

Creating an attenuator family - air flow problem

Revit Systems >> Technical Support

Wed, Jun 13, 2012 at 4:16:11 AM

4

Ductwork connected to air device displays flow in one model but not another

Revit Systems >> Technical Support

Fri, Nov 15, 2013 at 7:33:41 AM

0

I can't connect more than one VAV system to an Air Handling Unit

Revit Systems >> Technical Support

Tue, Oct 15, 2019 at 4:08:06 PM

0

Deleting an air termainal doesn't update CFM

Revit Structure >> Technical Support

Thu, Jul 19, 2012 at 10:35:56 AM

0

Site Stats

Members:

1963752

Objects:

22850

Forum Posts:

152159

Job Listings:

3

Sponsored Ads

Home | Forums | Downloads | Gallery | News & Articles | Resources | Jobs | Search | Advertise | About RevitCity.com | Link To Us | Site Map | Member List | Firm List | Contact Us

Copyright 2003-2010 Pierced Media LC, a design company. All Rights Reserved.

Page generation time: 1.1749

Login

User Name:

Password:

Remember Me  

Forgot Password?

Search Forums

Advanced Search

Search Forums

Advanced Search


Clear Highlights


Clear Highlights