I have 3 zones running off a tarm 60 with 1100 gallons of pressurized storage. I have a DHW zone on a sidearm on the propane 50 gallon hot water heater, and a main heat zone of a propane forced air furnace with a water to air coil in the plennum. The third zone is infloor tubes in a shop with 1-1/4" lines for transit. I have 2 Johnson control A419 24v aquastats. One will be threaded into the top foot of one of the storage tanks,the other will be threaded into a tee in the bottom of my DHW heater. All zones will have caffeli 1-1/4" zone valves of a grunfos Alpha pump. My question is how do I control my furnace. How does it know if it should ignite the burners if there is know heat in the boiler or tanks? Or how does it know to just turn on the blower fan and blow heat off of the coil. What if the boiler is hot and the tanks are not with zones calling for heat? Taco makes a 3 zone relay with priority. Is this what I need? I will show any imput to my electrician. Thank you for any imput.