Change duct system classification from EXHAUST to RETURN

[maan-L]

Hi!

Upon finishing my MEP model, I realized that I need to change the system classification from "EXHAUST AIR" to "RETURN AIR".

I tried to change it from properties but it doesn't show other classifications.

I also tried the edit system but it still didn't work!

[simon.locke · Accepted solution]

Unfortunately, it's not as simple as changing the system type from the properties. If you have equipment such as diffusers or FCU's attached then they will have connectors on them set to a system classification which should match the classification of the system you have connected to them (ie Return Air). If they are different then you would have got a warning about it as it will have been a mismatch. To change your system then you will 1st need to physically disconnect all of the air terminals and mech equipment from your system (anything with a defined system classification). Then you will need to edit duct system and remove all of the disconnected stuff from system, exit out of the editor. You will then be able to select a single piece of duct and change the system type from Exhaust Air to Return Air. You will also have to edit or swap your families out for ones with connectors to match the classification of your required system. Not a quick fix if it is a large system I'm afraid.

I hope this helps you out.

[Anonymous]

Did you model it using MEP parts or just Duct systems?

[RobDraw]

@simon.lockeis correct. The connectors being used for the exhaust system equipment, terminals, even fittings will get in the way of switching to a different system.

[mttmoe53]

I mean how to create such as fresh air, toilet, kitchen exhaust and need to change their represent color. Now, in Revit. There is only Exhaust, Return, and Supply air with only 3 colors. Please give me some advise. Thanks

[iainsavage]

Choose which Classification that you want (Supply, Exhaust or Return). Right click and duplicate the built-in system which corresponds. Change the name. Edit the system graphics overrides or create view filters based on system name, type, or abbreviation.

[brett.s.sandusky]

One thing the newer Revit allows is to edit the system under modify duct. In other words, select a component, click on duct systems tab, edit system, and then select the under the properties window which system you want it to be connected to. Not sure how long this feature has been available, but it helps me when the duct system is connected to the wrong family when attached to equipment.

[HVAC-Novice]

Huh? I never knew that nor tried. but wouldn't that be in conflict with what the connectors are classified as? 

Like the air terminal being " supply" determines what the duct attached to it will be. if you now set the duct to " Return", that wouldn't work and flows don't compute. Is there some trick to resolve this? 

This is the reason I only use " return" and not exhaust. Because I didn't want two separate families of return grilles (since they could be connected to return or exhaust). I'm happy to learn I was wrong and there actually is a solution. 

[brett.s.sandusky]

Just so there is a picture associated with what i was describing, here is an example  (see clip) of my being able to modify which duct system to attach a particular duct to. In this case I have 4 types of ducts connecting to a DOAS.  Supply, Outside Air, Return, and Exhaust.  In this case, my created outside air duct system could be changed to supply air, or supply air - high pressure.  This has helped me to fix some of the issues i have faced with manufacturer created models not matching the duct systems we have in a particular project.