On a refrigerant page's Pressure–enthalpy diagram, the readout says “Not solved here” where CoolProp, which computed the diagram, gives no state. Those areas are shaded, and nothing is drawn across them.
Why
Every state on the diagram is a CoolProp state, tabulated in advance and read between the points of that grid. Where CoolProp couldn't solve a point, any state shown there would be filled in from its neighbours, so Kelvin shows none. It happens outside the equation of state's temperature range, and across any saturation rows CoolProp didn't solve.
“Outside the tabulated range” is different: you're pointing past the edge of the diagram's grid.
What to do
- 1
Read the lines under the diagram. They give the temperature range CoolProp solves the refrigerant over, and any pressure bands it didn't solve.
- 2
Point at a state inside the solved area.
Note
Just below the critical pressure, the dome closes faster than the grid follows, so the readout gives no quality there and says so.
Every refrigerant's page is listed in the refrigerant tables.