I received such great advice on my first problem I decided to ask about my second.

I have a 4600 sf house running off two a/c's and furnaces - one for upstairs and one for downstairs.

The upstairs has two zones (at least I think that is what it means when you have two thermostats?) and presumably a damper in the attic (again?).

In my experience, the a/c (and perhaps heat but certainly a/c) only runs for the play-room over the garage zone when the main zone (master bedroom) is triggered and running.

I hope I have defined the issue accurately. How would a tech investigate a problem like this - do they have to go up to the attic?

Thanks for advice or questions!!