unique system

i am looking at a unique project and need 190 degree water but the owner wants a simplistic boiler but his btu demand can go from 15,000 btus up to 300,000 btus. He doesnt really want a modcon boiler as he is wanting a "basic" boiler but it needs to "stage" or "modulate" to meet his demands. Efficiency has no real bearing on his need. Anyone know of a unit that can do this?

Doubt you will find a basic boiler with that kind of turn down rate. Aerco would probably fit your need but it is far from basic.

300,000 cast iron with an injection pump controlled by a tekmar.