Boiler repair in north and east London

Some breakdowns are not faults at all. These checks are safe for anyone:

• Is gas reaching the house? If you have a gas hob, does it light? If it does not, the problem is the supply, not the boiler.
• Is the emergency control valve on? The handle by the meter should line up with the pipe.
• Prepayment meter? Check there is credit.
• Pressure gauge. Many sealed systems sit around 1 to 1.5 bar when cold, but follow your manual.
• Frost. If it is freezing and the boiler has locked out, the condensate pipe outside may be frozen. Pour warm, not boiling, water along it (Worcester Bosch), then reset.

Do not take the casing off. Anything inside the boiler is gas work.

Every Thames Water zone we cover is hard. The 2025 reports give average hardness of 268 mg/l in Hackney West, 276 mg/l in Bethnal Green and Kentish Town, and 278 mg/l in Hackney South (Thames Water zone report). Thames Water's own scale counts anything from 200 to 300 mg/l as hard.

In a combi boiler, that limescale settles in the plate heat exchanger, the small part that heats your tap water. Hot water goes lukewarm or swings between hot and cold. In the main heat exchanger, scale and sludge cause kettling, a rumbling sound like a kettle coming to the boil. Both are common call outs in E8, E2 and NW5.

Pressure loss is the other big one. Many Victorian terraces in Stoke Newington, Islington and Tottenham were split into flats decades ago. The heating pipes for an upstairs flat can run under floorboards and through ceilings of the flat below. A slow weep from a radiator valve or a joint under the floor drops the pressure bit by bit. The engineer checks the boiler's pressure relief valve and expansion vessel first, then traces the system.

A repair makes sense when the boiler is sound and parts are available. When a boiler is old, the heat exchanger is badly scaled, or the same faults keep coming back, a new boiler may cost less over time. You get the facts on both and you decide. See new boiler installation for how a replacement works.

The more we know before the visit, the more likely the right part is in the van. Send the make and model from the front or underside of the boiler, the fault code on the display, and what the pressure gauge reads. Tell us whether hot water, heating or both have stopped, and whether it happened suddenly or has been getting worse. Mention if the boiler is in a loft, a high cupboard or a flat with a shared entrance, and where the engineer can park. If you rent, tell your landlord or agent first, because the landlord is responsible for repairs from wear and tear and may have their own engineer.