unitary water-to-air heat pump capacity curve

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In E+ Engineering Reference (e.g. v23.1.0), for Unitary Water-To-Air Heat pump, Coil:Cooling:WaterToAirHeatPump:EquationFit uses the reference and curve fit below to calculate Qtotal, Qsens and Powerc.

When I used the curves (A1 to A5) from one of the Resstock model to calculate the Qtotal, I found that the Qtotal/Qtotal,ref falls between 0.8 to 1.0, even when the Vw is 0, i.e. when there's no cooling load, based on hourly output.This makes me think whether Qtotal is the hourly cooling rate of the coil or something interim result that needs to be normalized based on part load first before calculating the hourly cooling rate.

Any thoughts?

Appended, the curve in my os model for cooling.

Curve:QuadLinear,
  ground source heat pump clg total cap curve, !- Name
  -1.57177156131221,                      !- Coefficient1 Constant
  4.60343712716819,                       !- Coefficient2 w
  -2.15976622898044,                      !- Coefficient3 x
  0.0590964827802021,                     !- Coefficient4 y
  0.0194696644460315,                     !- Coefficient5 z
  -100,                                   !- Minimum Value of w {BasedOnField A2}
  100,                                    !- Maximum Value of w {BasedOnField A2}
  -100,                                   !- Minimum Value of x {BasedOnField A3}
  100,                                    !- Maximum Value of x {BasedOnField A3}
  0,                                      !- Minimum Value of y {BasedOnField A4}
  100,                                    !- Maximum Value of y {BasedOnField A4}
  0,                                      !- Minimum Value of z {BasedOnField A5}
  100,                                    !- Maximum Value of z {BasedOnField A5}
  ,                                       !- Minimum Curve Output {BasedOnField A4}
  ,                                       !- Maximum Curve Output {BasedOnField A4}
  Dimensionless,                          !- Input Unit Type for w
  Dimensionless,                          !- Input Unit Type for x
  Dimensionless,                          !- Input Unit Type for y
  Dimensionless;                          !- Input Unit Type for z