How do I properly model enthalpy wheel exhaust in eQuest?

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Our typical designs for heat recovery air handling units involve an air handling unit with heating/cooling coils, supply fan, an enthalpy wheel and an exhaust fan. I fill out the necessary information in the Heat Recovery 1 and 2 tabs for the heat wheel. But where do we input data for the exhaust fan? would this be considered the same as the return fan on the Fans tab? I input the data for the exhaust fan under the return fan and it ended up getting doubling my heating water plant load. Why would that be? Any help is appreciated!