ZoneHVAC:ExhaustControl does not work

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A bug report.

I ran an ExampleFile 5ZoneAirCooledWithDOASAirLoop_ExhaustSystem.idf to see how AirLoopHVAC:ExhaustSystem works. The central exhaust fans in the idf file do not operate.

I identified the cause. Minimum Exhaust Flow Fraction Schedule Name in ZoneHVAC:ExhaustControl is left blank.

I/O Reference says "If left empty, the default value would be 1.0", but I doubt it. If this field is left blank, the default value seems to be 0.

For now, enter a schedule including 1 (usually the same as the fan availability shcedule) in Minimum Exhaust Flow Fraction Schedule Name and the associated exhaust fan will operate.