Welcome! Here are some tips for using this forum.
White Rogers 1050 Indoor-Outdoor Control
Does anyone have first hand knowledge if the WR 1050 Indoor- Outdoor Hydronic Control (reset ratio) will work on a 750 Millivolt system? WR said it will only work with line voltage but the instructions show both line voltage and 24 volt wiring diagrams. I am working with an Amish contractor who builds Gravity Hot Water/ Millivolt systems and wants to use this control.