Central heating
Radiator valves are small parts that do a lot of work. When one leaks, sticks or stops controlling the heat, replacing it is usually quick and makes the whole room easier to live with.
Most radiators have a valve at each end. The control valve is the one you turn: either a plain manual valve or a thermostatic radiator valve (TRV) with a numbered head that adjusts the flow based on the room temperature. The lockshield at the other end sits under a plastic cap and is set once to balance the system.
Either can fail. Old valves seize, seals wear out, and TRV pins stick so the radiator is either always on or never comes on.
Sometimes the valve body is fine and only the thermostatic head has failed. A new head can be fitted without touching the water, as long as it is compatible with the valve body. If the body is old or leaking, it is better to change the whole valve.
To change a valve body, the water has to be stopped from flowing out. Depending on the system, that means draining the heating down, partly draining it, or freezing the pipe on each side so the valve can be swapped without emptying the system. The old valve comes off, the new one goes on with fresh joints, and the system is refilled, bled and brought back to pressure.
If several valves are old, doing them all in one visit saves draining the system more than once. It is also a good time to fit TRVs to radiators that still have manual valves, which gives you room-by-room control.
The number of valves, the type you choose, whether the system has to be drained and whether the pipe tails are in good condition all make a difference. Chris will explain the options before he starts. If a radiator is leaking from the panel rather than the valve, see radiator installation instead.
Not sure the valve is the cause? Our guides on a radiator leaking and radiators not heating up help you check. Valves are part of our wider central heating work. Send a photo of the valve to 07429 632804 on WhatsApp, or use the quote form.
Common questions
Clear answers before you arrange a visit.
A valve on the pipe into or out of a radiator that controls how much hot water flows through it. Most radiators have a control valve and a lockshield.
A thermostatic head can usually be swapped without draining. Changing the valve body needs the water stopped, by draining or by freezing the pipe, so it is best left to a plumber.
It is best not to. Paint can stop a thermostatic head moving freely and makes it harder to turn or service later.
Yes. Some radiators are designed with top connections, and there are valves made for that layout. The radiator needs to suit it.
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