How do I display certain ducts in certain viewports?

I have a number of ducts in my drawing. Some of them are at a certain elevation, while others are not. I can not display all of these on the same layout as it becomes too messy. How can I make one layout for some ducts, and another for the others. I usually make use of the option to freeze certain layers in certain viewports, but as all of these ducts are on the same layers I'm not able to. Ideas anyone?

If they're all on the same layer, then does this mean that they're all the same System? For instance, are they all Supply System? Surely you have Return Air and Exhaust Air at the very least.

When things get too cluttered, usually that tells you it's time for an Enlarged Area Plan. Is this an option for you?

You need to look into display be elevation to turn on/off ducts at specific elevations.

When things get too cluttered, usually that tells you it's time for an Enlarged Area Plan. Is this an option for you?

They are the same system yes. Not familiar with the term "enlarged area plan". Could you elaborate?

You need to look into display be elevation to turn on/off ducts at specific elevations.

I messed with such an option some time back - couldn't make it work. You got a way?

Here's a recent example job:

https://dl.dropboxusercontent.com/u/4989089/Images/cadtutor/M-Sheets.pdf

Refer to sheet M-2, column grid L,4. Notice the leader + note stating "refer to ..... for enlarged plan". Now go to M-6 and see the enlarged plans.... which are a larger scale and can relay information more clearly. The "Partial Plan" is 1/8" = 1'-0", and the "Enlarged Plan" is 1/4" = 1'-0". This is a very common practice for cramped or cluttered floorplans.

Hope this helps.

You can also use Project Navigator and set your levels to elevation zones, similar to what you would do for floor levels. Or set your duct systems to different layers and freeze them by view port in your layer manager.