The Taco Radiant Mixing Block is a complete injection mixing system. Integral to the unit is a variable speed injection circulator, constant speed system circulator, air elimination, and the electronics to drive it all. With only four piping connections needed, the RMB greatly reduces the time and space required for installation. The RMB can be set up to operate as an outdoor reset control or a setpoint control with or without delta T limiting, creating flexibility never seen before in a single unit.