Check for visible leaks first — radiators, valves, and pipe connections are common culprits. If you find a leak, place a tray underneath and call a plumber or Gas Safe engineer. If there are no visible leaks, the boiler may have a faulty pressure relief valve, expansion vessel, or filling loop — get a qualified engineer to diagnose and fix it.

Yes. If there are no external leaks, the issue is often internal: a faulty pressure relief valve, a leaking heat exchanger, or a problem with the expansion vessel. These require diagnostic checks and should be handled by a Gas Safe engineer to avoid safety risks.

Turn off the heating and let the system cool. Place a cloth or tray under the bleed valve, insert a radiator key, and turn the valve anti-clockwise until you hear a hiss. When water begins to drip steadily, close the valve. Check system pressure afterwards and top up if needed (follow your boiler manufacturer's instructions).

Noises are often caused by thermal expansion, pipes rubbing against joists or floorboards, or sagging pipe runs. Simple fixes include securing pipes with clips, packing felt where they pass through floors, or lifting sagging runs. If the noise is persistent, an engineer can inspect for trapped air, flow issues, or system imbalance.

Kettling — a loud knocking or banging — is usually caused by scale or sludge build-up restricting water flow and creating local hotspots. A system powerflush or chemical clean typically clears debris; replacing corroded components or fitting a magnetic filter may prevent recurrence. Have a Gas Safe engineer diagnose the cause before attempting repairs.