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[EnergyPlus_Support] How can I simulate a stuck open economizer?

I need to simulate a stuck open economizer damper. To do this I thought I could use an EMS program to override the outdoor air flow rate setpoint.

First I ran the simulation normally and found the maximum yearly outdoor air flow rate, which happens to be around 3 kg/s.

Next, in the EED file I found what I think it is the suitable actuator:

EnergyManagementSystem:Actuator Available,VAV_1_OA_CONTROLLER,Outdoor Air Controller,Air Mass Flow Rate,[kg/s]

Next, I did setup the EMS actuator and program, like this:

EnergyManagementSystem:Actuator,
    AHU1_OA_Flow,            !- Name
    VAV_1_OA_CONTROLLER,     !- Actuated Component Unique Name
    Outdoor Air Controller,  !- Actuated Component Type
    Air Mass Flow Rate;      !- Actuated Component Control Type

EnergyManagementSystem:Program,
    set AHU1_OA_Flow=10.0,   !- Program Line 2

When I run the simulation, the outdoor flow rate is, indeed 10 kg/s, but the problem is that E+ shows the "Actual Outdoor Air Fraction" greater than 1. How can this be? Should not this value be strictly between zero and one?
Furthermore, if I put a **very** large setpoint, e.g. 600 kg/s, E+ does not converge to the solution. Why?

Then, the larger questions are: Have you done something like this? Am I in the right track? Do you have any advise?

I posted my idf in the "Files" section at:
Files > _Problem_Submittals > EconomizerOpen.idf

Thanks.

Homero



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