Smart zoning thermostat or wiring centre shows 'Valve Err'; associated zone does not heat.

Safety first: Zone valves are usually connected to mains. Isolate heating system power at the fused spur before touching any valves or wiring.

• Identify the zone: Determine which radiator or underfloor zone is affected by the error.
• Check actuator position: Locate the corresponding motorised valve (e.g. Honeywell, Drayton, or Worcester‑branded) near the manifold or pipework. Check if the manual lever moves freely and if the valve can be latched open.
• Inspect wiring: At the wiring centre, verify that the thermostat output for that zone is securely connected to the valve actuator terminals.
• Test actuator (advanced): With power restored and a call for heat from that zone, feel if the actuator warms slightly and listen for movement. No movement suggests a failed actuator.
• Replace actuator head: Many valve heads are replaceable without draining the system. A heating engineer can swap the actuator head and test the end‑switch operation.