Boiler Repair London

Fast boiler repair across London

When your boiler stops, you need a Gas Safe registered engineer who turns up quickly, finds the fault properly and fixes it at a fair price. Our boiler repair London service covers every borough, from flats in Islington and Hackney to family homes in Croydon, Ealing and Bromley. We repair combi, system and conventional gas boilers from all the major makers, and we give you a fixed written quote before any parts are fitted — no surprises on the invoice.

Whether you searched "fix boiler London" at 7am with no hot water or have a boiler that keeps losing pressure, the process is the same: we diagnose with proper test equipment, explain what has gone wrong in plain English, and get your heating back on — usually on the first visit.

Common boiler faults and error codes, explained plainly

Most modern boilers show a fault code when they lock out. The exact codes differ by brand, but these are the ones London households ask us about most:

• F22 / low pressure codes — the boiler has detected too little water in the heating system. Often caused by a leak, a weeping radiator valve or a failing pressure relief valve. Topping up may get you going, but if pressure keeps dropping there is an underlying leak to find.
• F28 / F29 / ignition failure codes — the boiler tried to light and couldn't, or the flame went out. Causes include a gas supply problem, a faulty ignition electrode, a blocked condensate pipe or a failing gas valve.
• Frozen condensate pipe — common in cold snaps. The boiler locks out because waste water can't drain. We thaw and, where needed, reroute or lag the pipe so it doesn't happen again.
• Overheat and pump faults — water isn't circulating, often due to a seized pump, sludge in the system or an airlock.
• Fan and flue faults — the boiler can't confirm the flue is clearing combustion gases safely, so it shuts down. This always needs an engineer.
• No hot water but heating works — usually a diverter valve or flow sensor fault on a combi boiler.

Never remove the boiler casing yourself. If you smell gas, turn off the supply at the meter and call the National Gas Emergency number on 0800 111 999 before calling us.

Repair or replace?

We fix far more boilers than we replace, and we will always tell you honestly which makes more sense. As a rule of thumb, a repair is worth doing when the boiler is under 10–12 years old, parts are readily available and the repair costs a small fraction of a new installation. Replacement starts to make sense when the heat exchanger has failed, parts are discontinued, the boiler breaks down repeatedly each winter, or an older non-condensing model is costing you heavily in gas.

If replacement is the better option, we explain why and give you a separate written quote — there is no pressure to decide on the spot. Keeping a repaired boiler reliable is easiest with a yearly boiler service in London.

Our response promise

We work 7 days a week from 7am to 9pm. Call before midday and we aim to attend the same day anywhere in London; later calls are booked for the next available slot. Our vans carry the most common parts for leading brands, so many repairs are completed during the first visit. Where a specific part must be ordered, we tell you the lead time and the fixed price before leaving.

Every engineer is Gas Safe registered and shows their ID card on arrival. Need a specialist for your make? See our domestic boiler brand repair pages or our Gas Safe boiler engineer page.