Review on Taco SR503 4 Zone Relay for Enhanced Switching and Control by Daniel Russell

We have a 40 year old house that is heated by a boiler and three old relay controlled hot water circulating pumps that hummed very loudly and were a mess of wires. Although I had never touched a heating system before, I was able to replace the relay with this one box, which eliminated and simplified all the wiring to the circuit, thermostats and pumps. If I had known how easy it is to make it myself, I would have tackled this project a lot sooner. It's been working great (and quietly) for two winters now. I found the instructions easy and appreciate the indicator lights that let you know instantly when a particular zone is "working". Overall, I'm very happy with the Taco switching relay.