So, I purchased a ‘56 3100 with a Deluxe Heater in which the previous owner had installed a new (repo) heater control valve. I spent several hours trolling through posts related to heater control valves and didn’t see any which revealed exactly how this particular valve works (1955 - 1959).

I understand well how earlier ones with the capillary tube work, but this one has no capillary tube. I see a slug of springs and cams (or levers) but it is not obvious to me how this thing is designed to operate. Anyone have any definitive insight how this valve regulates… if indeed it does?

Thanks,
Greg