Central heating — London
Radiator not working in London?
Cold radiators, one radiator not heating, radiator cold at top or bottom — diagnosed and fixed by Gas Safe engineers across all London boroughs. From a quick bleed to a full power flush.
Diagnose your radiator fault
Radiator problems we fix in London
Cold at top, warm at bottom
Likely cause: Air trapped inside — bleeding required
DIY bleed with radiator key. If pressure drops, repressurise boiler.
Cold at bottom, warm at top
Likely cause: Sludge build-up at base
Single radiator flush or full system power flush
Completely cold — all others warm
Likely cause: Closed valve or seized TRV
Check TRV setting and lockshield valve. Engineer if valve seized.
Radiator leaking from valve
Call engineerLikely cause: Failed valve packing or gland nut
Valve replacement. Tighten gland nut as temporary fix.
Radiator leaking from pinhole in panel
Call engineerLikely cause: Internal corrosion perforation
Radiator replacement — cannot be reliably patched
Radiator making banging noise
Likely cause: Trapped air, sludge, or loose pipework
Bleed first. If persists, engineer to investigate
Related services
Central heating services in London
Common questions
Radiator problems London: frequently asked
Why is my radiator cold at the top but warm at the bottom?
A radiator cold at the top but warm at the bottom has air trapped inside. Bleeding the radiator — opening the bleed valve to release the air — will resolve this in most cases. Turn off the heating, let it cool slightly, open the bleed valve with a radiator key until water flows steadily, then close and repressurise the boiler if needed.
Why is my radiator cold at the bottom but warm at the top?
A radiator cold or cool at the bottom with warmth at the top typically indicates sludge (magnetite) build-up at the base of the radiator restricting water flow. Bleeding will not resolve this — the radiator needs flushing or the system needs a power flush to remove the sludge.
Why is one radiator not working when all the others are fine in London?
A single cold radiator when others are working is usually caused by: a closed lockshield valve (the non-adjustable valve that may have been accidentally turned off), a seized TRV (thermostatic radiator valve) stuck in the closed position, or a severely sludged radiator. Check the TRV setting and that both valves are fully open before calling an engineer.
When should I replace a radiator in a London property?
Replace a radiator when: it has a pinhole leak that cannot be repaired (corrosion from inside), it is heavily corroded externally, it is a very old single-panel radiator that would benefit from a larger double-panel replacement, or it is cold in the middle despite flushing (collapsed internal structure). New radiators are inexpensive — a standard double-panel radiator typically costs £50–£150 plus fitting.