Different volume flow rate in supply and exhaust using AFN

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Hi everyone,

I am trying to model a single dwelling using airflow network. My task is to create a different supply and exhaust volume flow rates (using for example Schedules) for each zone individually. I want a DOAS. I already managed to model the desired exhaust volume flow rate using the Fan:Exhaust object. I tried to model the supply fan as an ideal system (ZoneHVACIdealLoads) and using an air terminal with an uncontrolled constant volume fan (AirTerminal:SingleDuct:Uncontrolled). In both cases the HVAC system (ideal or air terminal) creates an additional supply or exhaust airflow, to keep the mass balance equal, even though I deactivated the mass flow balancing option for the zones. I tried as well to model a ConstantVolume:Fan, obviously again unsuccessfully.

I would appreciate if anyone has an idea how to solve this modelling issue.

Thanks in advance :)