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This is only a partial diagnosis of your question.

Right now your chiller is set to constant flow, in the .idf:

  ConstantFlow,                           !- Chiller Flow Mode

And your setpoint manager is controlling the outlet temperature, keeping it fixed at 5oC (Actually I think the setpoint is set at 0.5oC but the minimun loop temperature forbids it from going lower).

With constant flow and fixed outlet (Impulsion) temperature, the only variable for the heat balance to satisfy the demand is changing the return temperature. (In Q=mSpDT; m=cte; Sp=cte; DT=T_return-5).

Here is the input output guide of the chiller for other modes of modulation: https://bigladdersoftware.com/epx/docs/24-1/input-output-reference/group-plant-equipment.html#field-chiller-flow-mode

Two possible solutions I can think of:

1. Change the HVAC system to use variable flow and somehow keep the DT fixed (I myself don't know how to make that work in EP). Keep in mind that also the pumps should change to variable flow in this case.
2. Keep the constant flow but control the return temperature instead of the evaporator outlet (Impulsion) temperature. I found degree of success with this approach using water-to-water heat pumps and the return temperature setpoint manager (https://bigladdersoftware.com/epx/docs/24-1/input-output-reference/group-setpoint-managers.html#setpointmanagerreturntemperaturechilledwater)

If you find a solution that works, I encorage you to post it here!

Good luck with your simulations, PMP