You are correct, there is no limit on the number of plenums on a
system. I took a wizard created model, two floors, 5 PSZ per floor
with a plenum on each system. I moved all the plenums to a new PVAVS
system with one conditioned zone and the 10 plenums.

This is for my ruleset development - the many to one case where the
many system each have a plenum zone. With DOE2.1e you could not have
more than 3 plenums on a system.

Re. restrictions - I know DOE2.1e has a number of system types that
do not allow plenums. I need to read closer.

>> Christopher Jones, P.Eng.