No Hot Water — What to Do

Confirm whether cold water is still running. If both hot and cold have stopped, the issue is supply or isolation (stopcock, building riser or street works), not just the boiler. If only hot has failed, note whether heating still works — that distinction points to combi hot-water faults, diverter valves, cylinder stats or immersion heaters.

For combination boilers, check the display for fault codes, confirm the boiler has power and that the timer or programmer is set to allow hot water. Check system pressure (often around 1–1.5 bar when cold). Do not keep repressurising if pressure falls again within hours — that usually means a leak somewhere on the system.

For systems with a hot water cylinder, check the cylinder thermostat, the motorised valve and whether the immersion (if fitted) still heats. In many Chelsea mansion blocks, shared plant or a failed local cylinder can leave one flat without hot water while neighbours are fine.

If checks do not restore hot water, call Emergency Plumber Chelsea on 020 3002 6667. We diagnose combis, system boilers and cylinders across SW3 and SW10 and explain repair options before work starts. If you smell gas at any point, leave and call National Gas Emergency 0800 111 999.

Quick tips

• Write down any boiler fault code before resetting — it saves diagnostic time.
• Do not repeatedly reset a boiler that locks out; find the underlying fault.
• If only one tap has no hot water, the problem may be a failed mixer or local isolation, not the whole system.
• In winter, treat no heating and no hot water as a priority call-out, especially for vulnerable households.

FAQs