I just put my furnace in (Weil McClain WGO4 / "Less tankless") and it came with the HONEYWELL AQUASTAT CONTROLLER L7248A. The problem is that I do not believe this controller is set up for an INDIRECT HOT WATER TANK with it's own circulation pump. My TACO relay allows the Hot Water Tank's circulation pump to come on <(wired to the controller) which pulls from the boiler, but the AQUASTAT CONTROLLER L7248A DOES NOT have a terminal connecter "ZR". <This terminal connection should allow for the furnace to come when when the 15 degree differential is met. As of now, the only time the Furnace cycle is when the Zones are calling for heat.

I need a CONTROLLER (or relay??) that will allow the Boiler to cycle when the HOT WATER TANK pulls from the boiler and drops the Tempature in the boiler below the 15 degree differential. I believe it the proper controller would be the AQUASTAT L7224A or L7224U??

Hope I did not confuse you with the lengthy explaination. Can you help me out?? I do not want to spend needless money on something that is not correct.

Thanks