Good Morning Everyone,

I have a few quick questions about phasing in Revit MEP 2013. I have just recently started to use revit MEP 2013 ( we got building design suite premium for 4 years ) I am pretty familiar with the revit as a software ( previous came from a position were we designed baggage handling systems for airports, and we used revit architecture 2012, 2011 to accomplish this.) @ my previous position using the phasing feature was great when doing small airport upgrades or improvements. My question is how do you go about using the phasing in MEP? I have been working on a small job that is an overall building improvement / upgrade and we will be tying into a majority of the existing HVAC / Plumbing & Electrical. I have noticed that once you set a string of duct work and a AHU to existing phase and to be demoed in the appropriate phase the system is now undefined and i can not change this. What would be the correct way of showing phasing in MEP models.

Thanks
Josh