ZVC403-5 - 3 Zone Valve Control with Priority, Bluetooth & Taco Control AppTaco ZVC403 5 3 Zone Valve Control with Priority, Bluetooth & Taco Control App The Taco ZVC403 5 3 Zone Next Generation Valve Control with Priority is a clean, reliable way to manage up to three heating zones using 24V zone valves. Built for hydronic systems, it gives you simple thermostat inputs, clear diagnostic LEDs, and a built in priority switch to protect your domestic hot water zone when needed. With a compact layout and easy wiring, the ZVC403