I have Base board hot water system.It has 5 thermostats with 5 zones. It operates with Taco SR504switching relay plus SR503 expansion relay. I can not use the power from the taco units and would like to use a external 24v source. I have tried and even spoke to Taco but for some reason I do not get 24v out of transformer. So the work around would an external 24v transformer. Right now I have a Red and White wire going to old therm. I have two extra wires in wall to use going to the boiler. If I use external 24v transformer,where do I put the two wires going into the RTH8580WF.I have an idea but would like some one with more experience to put there two cents .