I want to setup a system where the OA volume is set to 0 for setback
heating/cooling. Under the help for "Minimum Air Schedule", it says
that you can set up a schedule where the values for min OA range from 0
to 1.0, but a value of -999 defaults that particular hour to whatever
the zone calcs require.

This is perfect, except the only type of schedule that you can input
into MIN-AIR-SCH is type FRACTION, and the FRACTION schedule won't
accept -999. Only from 0 to 1.0.

What am I doing wrong? Thanks in advance,

James Hansen, PE, LEED AP