I see these around once in a blue-moon. Could never find the iom for Honeywell T678B.
anyone know at what temp of osa this sets the set point up?
My understanding of this controller is:
1 bulb reads osa, the other reads the fluid temp to be controlled. As the Outside air temp drops, the temperature set at the controller dial increases at a 1:1 ratio. Correct me if i'm wrong here please.
find these on boiler loops, and roof top duct furnaces mostly.