Hi Chris,

eQuest will allow you to create a system without assigning a zone
(though the sim wouldn't run until you assign one). However it won't let
you assign a thermal zone without an unassigned space defined in the
project, which is leading to your error. So you have to work in reverse,
creating the unassigned space first.

There are two easy ways to do it:

1) Create a space in the Building Shell tab. Right click the top
line of your project tree and choose "create space." You can create a
dummy space that will at least allow you to assign a zone to your PVVT
system so you can start entering your specs. Back on the air-side tab,
when you select "Create child thermal zone" for your new system, the
second popup box will contain a drop down that includes the space you
created.

2) You might already have the zone defined that you'd like to put
on the PVVT. In this case, delete it from its current system under the
air-side tab. Then create your new system. The zone selection dropdown
will now include the zone you "deleted" (actually you only unassigned
it). Just pay attention to your control zones through the process. You
will likely have to go back and modify these after you get everything
set up.

Jason Kirchhoff