Boiler & heating troubleshooting guides
Diagnose boiler faults including ignition problems, pressure issues, kettling noises, lockouts and central heating circulation problems.
Common problems
Outside drain overflowing after heavy rain: surface water vs foul drainage
Advice Hub / Drains & Blockages Outside drain overflowing after heavy rain: surface water vs foul drainage Check time: 10–15 minutes • Difficulty: Easy checks • Safety: Low risk Quick answer If an outside drain or gully only overflows during or after heavy rain, this points more towards a surface water drainage issue — rainwater…
Water pressure dropping when a tap runs: what it can mean
Advice Hub / Water Pressure Water pressure dropping when a tap runs: what it can mean Check time: 5–10 minutes • Difficulty: Easy checks • Safety: Low risk Quick answer If pressure noticeably drops at one tap or fixture when another is turned on elsewhere, this is often about how flow is shared across your…
Radiator not heating after bleeding: what to check
Advice Hub / Radiators Radiator not heating after bleeding: what to check Check time: 5–10 minutes • Difficulty: Easy checks • Safety: Low risk Quick answer If a radiator is still cold after bleeding, trapped air likely wasn’t the actual cause — the real issue may be a closed valve, restricted flow, or sludge inside…
Radiator valve leaking: what to check and when to call a plumber
Advice Hub / Radiators Radiator valve leaking: what to check and when to call a plumber Check time: 5–10 minutes • Difficulty: Easy checks • Safety: Medium risk Quick answer A leaking radiator valve is usually caused by a worn seal, a loose connection, or a valve that’s not fully closed. In many cases you…
Boiler making a loud vibrating noise: what to check
Advice Hub / Boilers & Heating Boiler making a loud vibrating noise: what to check Check time: 5–10 minutes • Difficulty: Easy checks • Safety: Low risk Quick answer A vibrating or humming noise from a boiler is often different from banging or rumbling, and can be linked to the pump, loose panels, or fan…
TRV valve faults explained
Advice Hub / Radiators TRV valve faults explained Check time: 5 minutes • Difficulty: Easy checks • Safety: Low risk Quick answer A TRV (thermostatic radiator valve) is the valve, usually with a numbered dial, that controls how much hot water flows into a radiator based on room temperature. When it faults, a radiator might…
Heating system sludge explained
Advice Hub / Boilers & Heating Heating system sludge explained Check time: 5 minutes • Difficulty: Easy checks • Safety: Low risk Quick answer Sludge is a build-up of rust, debris, and mineral deposits that can accumulate inside radiators and pipework over time, especially if the system’s water isn’t properly treated with an inhibitor. It’s…
Radiator balancing explained
Advice Hub / Radiators Radiator balancing explained Check time: 5 minutes • Difficulty: Easy checks • Safety: Low risk Quick answer Balancing is the process of adjusting radiators so that hot water flows evenly around your heating system, rather than the nearest or largest radiators taking most of the flow and leaving others lukewarm. It’s…
PRV valve discharge explained
Advice Hub / Water Pressure PRV valve discharge explained Check time: 5 minutes • Difficulty: Easy checks • Safety: Low risk Quick answer The pressure relief valve (PRV) is a safety device that releases water from your heating system if pressure gets too high, protecting the system from damage. If you notice water dripping or…
Expansion vessel failure explained
Advice Hub / Water Pressure Expansion vessel failure explained Check time: 5 minutes • Difficulty: Easy checks • Safety: Low risk Quick answer An expansion vessel is a component that absorbs the extra volume of water as it expands when heated, helping keep pressure stable in a sealed central heating system. When it fails, pressure…