Zone Valve Failure
One zone or the hot water won't heat, or a valve buzzes continuously in the airing cupboard..
One zone or the hot water won't heat, or a valve buzzes continuously in the airing cupboard.
What is actually going on
One zone or the hot water won't heat, or a valve buzzes continuously in the airing cupboard.
The realistic causes, in order
A burnt-out synchronous motor in the actuator head A failed auxiliary micro-switch, so the boiler never receives the demand even though the valve opens A seized valve body, usually where system water quality has been poor
What we test on site
Whether the head drives the valve open under demand Micro-switch continuity and the orange switched-live it should generate Valve body movement with the head removed
Safe checks to make with a failed zone valve
- Listen for a buzz or hum at the valve when heating is called
- Check whether the manual lever is latched
- Most valve heads can be changed without draining the system, but the body cannot. That distinction affects the work involved and should be explained before starting.
Who does the work
- Gas Safe registered engineers — registration 554328
- Worcester Bosch accredited installer
- John The Plumb Ltd, company registration 10026483
Get a failed zone valve diagnosed properly
Head-only replacement is usually enough; a seized body is a sign the system water needs attention too.
Questions we get asked
What causes a failed zone valve on a gas boiler?
A burnt-out synchronous motor in the actuator head
What normally puts a failed zone valve right?
Head-only replacement is usually enough; a seized body is a sign the system water needs attention too.
Is it safe to keep using the system with a failed zone valve?
Most valve heads can be changed without draining the system, but the body cannot. That distinction affects the work involved and should be explained before starting.