Zone valve not opening — no heating in one area
Check the steps below first — if you're not confident, get it fixed safely today.
Post a job — we'll find you an engineer →⚠️ Zone valves contain electrical actuators — isolate the boiler and zone valve wiring before removing the actuator head.
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Most likely cause & what to check
A zone valve (also called a motorised valve) is an electrically operated valve that opens and closes to direct hot water to different circuits — typically upstairs/downstairs, or heating/hot water. If one zone has no heat, a stuck or failed zone valve is often the cause.
Locate the zone valves — they are typically in the airing cupboard, fitted to the pipework. Each valve has a cylindrical actuator (the electrical motor) clipped or screwed onto the valve body.
Check the manual override: most Honeywell and Drayton zone valves have a small lever on the actuator (a white or grey tab) that can be slid to manually open the valve. If sliding the override restores heat to the zone, the valve mechanism is okay but the electrical signal or actuator is faulty.
Check the wiring: confirm the thermostat for that zone is calling for heat (turn it up above room temperature) and the timer is in a heating period. If the thermostat is calling but the valve is not opening, use a multimeter to check that 230V is reaching the actuator terminals.
The actuator can fail independently of the valve body — remove it (a small screw or clip holds it) and replace with a new actuator (£15–£30 for Drayton or Honeywell, the two most common UK brands). The valve body itself rarely fails.
If a new actuator does not resolve it, the valve spindle may be seized from lack of use (common if the zone has not been used all summer). Try operating the manual override lever while gently tapping the valve body — this can free a stuck spindle.
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