Fluid-to-Fluid Heat Exchanger Warning: “Control type requires setpoint manager: HX 1 [closed]

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Hello everyone, I am modeling a data center with heat recovery using a Fluid-to-Fluid Heat Exchanger (HX) that connects the condenser loop (source side) with the hot-water loop (demand side). The control type I selected is “Heating setpoint modulated”, and I assigned the HX on the supply side of the hot-water loop before the boiler.

However, when running the simulation in DesignBuilder v7.3 (EnergyPlus), I get the following error:

Fluid-to-Fluid HX control type requires setpoint manager: HX 1 Error in HVAC definition already tried setting the HX availability schedule to “Always On,” but the error persists. Could anyone please explain where exactly the required setpoint manager should be added (on which side of the HX or which loop), and what type of setpoint manager (Scheduled, Heating, or other) is best for this configuration?

My goal is to recover heat from the condenser and use it for the hot-water loop while maintaining stable temperatures (≈ 45–50 °C).

Thank you in advanceC:\fakepath\2.jpg(/upfiles/17616125634222583.jpg)