Forums >> Revit Systems >> Technical Support >> REVIT MEP, Diffuser Airlfow Parameter isssue

AVSteve

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Once again, I apologize if this is a duplicate question, I am still very new. 

 In Revit MEP 2008 on the options bar for air terminals there is a box labeled "Flow:" with a box that shows what the air flow for that diffuser is set to.  If this number is changed in the box on the options bar the same parameter, 'Flow', in the diffuser properties will update itself to the new number. The problem I am having is that when I create a new custom designed diffuser family this link is non functional and I cannot figure out how to get it established.  Is there anyone here who has had a similar issue with this options bar paramater?  I appreciate any comments and I can respond again if I have not been clear enough. Thanks. 

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GarryR

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Steve:

 Open the diffuser family for editing.  Make sure "Flow" is an instance parameter.  Select the duct connector to the diffuser.  Select the associate parameter box of your flow parameter under "Mechanical - Airflow.  Associate the Flow parameter with the family parameter of flow.  Refer to attached jpg.

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AVSteve

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GarryR, Thanks so much for that tip. It's like it was hiding right in front of me. However, now the 'Flow' box does take the flow rate and plugs it into the diffuser properties but it will not show that info after I click out of the box and then click on the diffuser again, it just shows 0 CFM, even though the property is set to a certain CFM. Maybe this is just a bug. Anyway, thanks for your reply.

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GarryR

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AV Steve:

Have you set-up diffuser tags.  I get the CFM to show on diffuser tags, but cannot get the CFM to show in the flow box of the family edit bar.  We are probably still missing the setting of some parameter.  I worked all morning to get this proplem solved, and still feel it is only partially solved.

 GarryR

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AVSteve

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Garry,  Yes I have a custom made Diffuser tag that we use here.  The picks up the Flow just fine but like you said, It doesn't show on the family edit bar.  I can still enter the value into the edit bar and everything takes fine, but then the CFM value returns to 0 even though the parameter still carries the value I set it to.  Wierd.  The standard issue diffusers that come with Revit work just fine, so i think you are correct that there is some parameter or association somewhere that is off. 

Steve 

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AVSteve

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Garry,  Yes I have a custom made Diffuser tag that we use here.  The picks up the Flow just fine but like you said, It doesn't show on the family edit bar.  I can still enter the value into the edit bar and everything takes fine, but then the CFM value returns to 0 even though the parameter still carries the value I set it to.  Wierd.  The standard issue diffusers that come with Revit work just fine, so i think you are correct that there is some parameter or association somewhere that is off. 

Steve 

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AVSteve

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Garry,  I have finally figured out how to get the flows all set for diffusers.  It is a combination of associating the proper paramters as well as telling the connectors how to interact with other equipment.  When you look at the properties for any duct conector you will see the "Flow Configuration" setting.  If this is set to 'calculated' the flow info you enter into the diffuser will not show up on the options bar in your floor plan view, you must set it to 'preset'. The inplications of this setting, of course, goes deeper than just the flow box on the options bar.  If you follow this link: http://inside-the-system.typepad.com/my_weblog/2007/11/go-with-the-flo.html  you will find a very useful explantion of connectors, parameters and links.  Look at both part 1 and part 2.

Hope this will help someone. 

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autocadisfaster

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Joined: Fri, Sep 18, 2009
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