U235a4 wrote:ok I think I may have figured a few things out but let me go thru the running order with how I think your units running.
your unit runs untill it reaches the operating limit of 170 on the L4006a unit and if your using a timer the high limit of 190 won't let the unit run until it falls below that. if the temp goes above 205 the circulator won't run and your dead in the water till the unit cools
The L4006A is the operating limit and has a fixed differential. If the sensed coal boiler water temperature drops below the operating set point the draft blower comes on and runs until the L4006A is satisfied. The high limit is a backup to the operating limit and if the high limit is triggered it cuts power to the operating limit control to prevent operation of the draft blower. If the circulator override is triggered (sensed temperature of the coal boiler water greater than 205) then the circulator for the B coil in the air handler in the out building, as well as the fan in the air handler are turned on and remain on until the circulator override sensed temperature drops below the set point.
I have no timer.