Taco Zone Valve Controls simplify the wiring nightmare. They work with 2-, 3- or 4-wire zone valves and their easy-to-follow PC board layout eliminates the problems caused by incorrect wiring and the “unfinished” look of conventional zone valve installations. External indictor lights give you instant diagnostic feedback and reduce installation time. Use them combined with Taco Zone Valves and Thermostats to maximize system performance and dependability.