Emergency Plumbing & Boiler Repair · Fulham, London
Hot Water Cylinder Repair in Fulham
A hot water cylinder is the part of a home most people forget until the shower runs cold. Tucked into an airing cupboard, a loft or a basement, it stores the household's hot water, and when it fails the symptoms are blunt: lukewarm taps, a drip from a pipe outside, a pool under the tank. Emergency Plumber Fulham arranges cylinder repair and replacement through partner heating companies on 07898 117754, at any hour.
There are two families of cylinder. A vented cylinder, the traditional copper tank in an airing cupboard, is fed from a cold water tank in the loft and runs at low pressure. An unvented cylinder is fed directly from the mains and delivers strong showers, but it is a pressurised vessel under Building Regulations Part G3, with a temperature relief valve, expansion vessel and tundish that must all work. Which you have changes the repair and the safety questions.
Fulham has both in abundance. The Victorian terraces of SW6 and W14 often kept the old vented system for decades, while loft and basement conversions in Parsons Green and beyond introduced unvented cylinders to feed new bathrooms. Thames Water's hard supply, 266 mg/l calcium carbonate in its 2025 City-zone report, furs immersion elements and the coil inside a cylinder, which is why lukewarm water and tripped controls are such common calls.
The partner company quotes in writing before work begins, invoices you directly and takes payment itself. We handle no money, and we text you the company's name before they arrive. A cylinder usually works with a boiler, so if heating is the other half of the problem, see repair for a failed boiler or heating repair; for a pipe that has failed, burst pipe repairs.
What We Do
Cylinder Faults and What Causes Them
Lukewarm water, drips and noise each point somewhere different.
Lukewarm Water and Failed Heating Elements
If the water never gets properly hot, the cause is often a failed immersion heater, a stuck motorised valve, a thermostat set too low or a coil furred by scale. In hard-water Fulham, immersion elements can fail in a few years. The partner tests the thermostat and element, replaces what has failed and checks the timer or controls, which is usually a straightforward repair.
Dripping Tundishes and Discharge Pipes on Unvented Cylinders
A tundish that drips or an external pipe that discharges is a warning sign. Usually it means the pressure or temperature relief valve is passing, the expansion vessel has lost its charge, or the thermostat is failing. Do not block the discharge pipe, because it is a safety device. The partner diagnoses which part is at fault, and will tell you if the cylinder needs replacing.
Leaking, Corroded or Waterlogged Cylinders
A leak from the body of a cylinder, or a pinhole that weeps at a seam, cannot be mended in the long term, and replacement is the answer. Copper cylinders that have been in place for 20 years or more are prone to this. Published London ranges for 2026 put a fitted like-for-like unvented replacement at about £1,495 to £2,845, with the partner's written quote showing the real figure.
The Benefits
Repair, Upgrade or Replace: Making the Call
A cylinder's age, type and condition decide whether a repair makes sense.
Straight Advice on Condition
A cylinder under ten years old with a failed element is worth repairing, whereas one that is leaking, badly scaled or 20 years old probably is not. The partner should say which they think yours is, and give you the repair cost and the replacement cost side by side. The choice is yours.
Converting from Vented to Unvented
Many Fulham households replace an old vented cylinder with an unvented one to get mains-pressure showers and free up the loft tank. It is a larger job, covered by Part G3, with extra discharge pipework and checks on whether your mains supply can feed it. The partner can quote the conversion alongside a like-for-like replacement.
Safe Installation to the Right Standards
Unvented cylinders must be installed to the manufacturer's instructions and Part G3, with safety devices and a discharge route that works, and the installation is notifiable. Annual checks of the safety valves are recommended. The partner should give you the commissioning paperwork and explain how to check the discharge.
Why Us
Cylinder Calls Across Fulham's Different Homes
Where the cylinder sits and what feeds it varies from street to street.
Airing Cupboards and Loft Tanks in the Terraces
Many Victorian terraces still have a vented cylinder and a loft tank with an overflow pipe. When the tank fails, or the ballvalve sticks, water runs outside or into the ceiling. We ask about the layout when you call, so the partner brings the right parts. Our Parsons Green plumbers page describes the housing.
Basement and Loft Conversions
Conversions often add unvented cylinders in awkward spaces, with long discharge runs. A discharge that does not meet the rules is a common reason for an installation being questioned. The partner measures and quotes the discharge route, so there is no surprise on the day.
Flats in Mansion Blocks
In West Kensington's mansion blocks and converted houses, space is tight and pipe runs are shared, so a cylinder may be small, high up or in a cupboard. The partner can often fit a compact replacement. See W14 around West Kensington for the local building types.
Before the Partner Arrives
Safe Checks You Can Make Yourself
Check whether the immersion heater switch is on, the timer or programmer is set correctly and the cylinder thermostat is turned up, because a surprising number of cold-water calls end there. Feel whether the pipes leaving the cylinder are warm. On an unvented cylinder, do not touch the safety valves or block the discharge pipe, and do not open any valve you do not recognise. If the cylinder is hissing or very hot, switch off the heat source and call us.
Scale, Softeners and the Life of a Cylinder
Thames Water's hard supply, 266 mg/l calcium carbonate in its 2025 City-zone report, builds scale on elements and coils year after year, so cylinders in Fulham often age faster than the same model in a soft-water area. A scale inhibitor or softener on the cold feed slows it, and flushing and descaling during a service helps. The partner can tell you whether your cylinder has years left or whether replacing it now is the sounder choice.
Insulation and Running Costs
Modern cylinders are factory-insulated with foam, while older copper cylinders often wear a loose jacket that has seen better days. Heat that leaks from the tank into the airing cupboard is paid for twice, once on the fuel bill and once in a stuffy cupboard. If the cylinder is staying, upgrading the insulation and lagging the first metre of pipework is a cheap improvement that the partner can quote alongside any repair.
If the cylinder is working but the heating is not, see central heating faults; if the leak is on a pipe, hidden leak tracing or burst pipe page. The Fulham plumbing page has the overview, or call 07898 117754.
Frequently Asked Questions
Why is my hot water only lukewarm?
The usual causes are a failed immersion heater, a thermostat set too low or faulty, a scaled coil, a stuck motorised valve or a boiler that is not heating the cylinder properly. In Fulham, where Thames Water's supply is hard at 266 mg/l calcium carbonate in its 2025 City-zone report, scale on elements and coils is a very common cause. A partner can test the thermostat, element and valves in turn and repair what has failed.
What is a tundish and why is mine dripping?
A tundish is a visible funnel-shaped fitting on the discharge pipework of an unvented cylinder, designed to show if the safety valves are releasing water. If it drips regularly, a relief valve may be passing, the expansion vessel may have lost its air charge, or the thermostat may be failing and the cylinder overheating. It is a warning sign and should be checked promptly. Do not block the discharge pipe.
What is the difference between vented and unvented cylinders?
A vented cylinder is fed by a cold water tank in the loft and works at low pressure, which means weaker showers unless a pump is added. An unvented cylinder is fed directly from the mains, which gives strong flow at every tap, but it is a pressurised vessel covered by Building Regulations Part G3 and needs safety devices and regular checks. Which suits you depends on your mains pressure and household.
How much does it cost to replace a hot water cylinder in London in 2026?
Published 2026 London ranges put a like-for-like unvented cylinder, fully fitted, at about £1,495 to £2,845 for 150 to 300 litres, and some price lists show simple tank swaps lower. Costs rise if the discharge pipework has to be altered or the cylinder moved. The partner will give you a written quote, itemising the cylinder, labour and any extras, and you can compare it with those ranges.
Can an old copper cylinder be repaired?
Fittings on it, such as immersion elements, thermostats, valves and joints, can usually be replaced. A leak in the body of the cylinder itself cannot be repaired in the long term, and the cylinder would need replacing. Cylinders more than 20 years old are often best replaced when a significant fault appears. The partner should tell you which category yours falls into and give you the choices in writing.
Is it safe to keep using an unvented cylinder that is discharging water?
It depends on why it is discharging. Occasional small drips from expansion can be normal, but regular or increasing discharge suggests a fault in a valve, the expansion vessel or the thermostat, and a thermostat fault can lead to overheating. Do not block the discharge pipe. If hot water is coming out forcefully, turn off the heating source and the water supply to the cylinder, then call us immediately.
Do I need to tell building control about a new unvented cylinder?
Installing an unvented hot water storage system is notifiable under Building Regulations Part G3, which covers hot water safety and efficiency. A competent installer will notify or self-certify the work and give you a certificate. In Fulham the local authority is Hammersmith and Fulham. Keep the certificate with your property papers, because it may be requested if you sell the home.
Can I change from a vented to an unvented cylinder to get better showers?
Often, yes, provided your incoming mains supply has enough pressure and flow. The old cylinder and loft tank are removed, a new unvented cylinder is installed with its safety devices and discharge pipe, and cold supplies may need to be re-routed. The partner will check the supply first and quote the work. Not every house suits it, and they should tell you honestly if yours does not.
How long does a cylinder replacement take?
A like-for-like replacement normally takes a day, with hot water off during the work. A conversion from vented to unvented can take longer because of the extra pipework and discharge route. The partner will give you an estimate in the quote and tell you what to expect for the day. If you have no hot water, they may suggest fitting an immersion heater temporarily.
Do you cover cylinder repairs across West Brompton and Sands End?
Yes. We cover Fulham, Parsons Green, West Kensington, West Brompton, Sands End and Imperial Wharf. Riverside apartments often have modern unvented cylinders or heat interface units, while older houses have vented tanks. Tell us your postcode and what type of home you have, and we will match a partner who has done the right kind of work before.
No Hot Water? Get a Cylinder Specialist
Partner heating company, written quote, any hour. Call 07898 117754.
07898 117754