XFiire 650 firing rate problem

Mkowal5220

Having a problem with the firing of a Raypak XFiire. This boiler is oversized for the building but I would like to de-rate or limit the maximum firing rate if possible. This boiler overshoots the setpoint and ends up tripping the high limit which drops out the burner causing a no heat condition. Has anyone else ran into a similar problem such as this or knows of way we might me able to limit the max fire? I haven't had much luck with the vendor to see if they know of a way to do this, they did program it to a glycol setting but that didn't help much. Other Raypak boilers we have installed have had an adjustable max setting but of course not this one.