Riello 40 GS10/M progressive or modulating gas burner

The Riello 40 GS 10/M is part of a series of two-stage progressive or modulating gas burners for residential and soft industrial applications. It offers a heat ouput of 22/42-105kW. The basic models offers two-stage progressive operation. A simple modification permits obtaining modulating operation with a 1:4 ratio. The more advanced version is