Comment 1 for bug 1987643

Offending line:
SuperheatRefTempF = (Me2.ToFt2(SuperheatAreaM2) * C.ToF(C.FromK(MaxFlueTempK)) * SuperheatKFactor) / pS.TopH(TheoreticalMaxSteamOutputLBpS);

It may be that ORTS code should be (moving two paren):
SuperheatRefTempF = (Me2.ToFt2(SuperheatAreaM2) * C.ToF(C.FromK( MaxFlueTempK * SuperheatKFactor )) ) / pS.TopH(TheoreticalMaxSteamOutputLBpS);

If I could figure out what that SuperheatKFactor had for units, it would help.
But it still leaves you with the rest of the equation being a ratio upon a temp in degree F, which cannot be valid. You need degree K to multiply ratios like that.
That conversion to degree F involves adding some constants, so it does not act like a const multiply.

So my best guess is that it should be (moving conversion to F around entire result):
SuperheatRefTempF = C.ToF(C.FromK( (Me2.ToFt2(SuperheatAreaM2) * MaxFlueTempK * SuperheatKFactor) / pS.TopH(TheoreticalMaxSteamOutputLBpS) ));