This section applies when free cooling current mode is dual enthalpy.
For dual enthalpy economizer operation, the outdoor air enthalpy must be lower than the return air enthalpy by 1 BTU/lb and the operational outdoor air temperature is less than the outdoor air temp enable setpoint (EconOAT-SpEn).
Free cooling is no longer available if the operational outdoor air temperature rises above the outdoor air temp enable setpoint (EconOAT-SpEn) or the outdoor air enthalpy rises above the economizer outside air enthalpy setpoint.