Boiler repair in London
The heating has stopped, the hot water has stopped, or the boiler has locked out and is flashing a code at you. Ninja Plumbers diagnoses the actual fault before quoting anything — no guesswork, no swapping parts to see what sticks — then gives you both numbers, repair and replacement, and lets you make the call.
- Gas Safe registered and fully insured
- DBS-checked engineers
- Emergency callout available 24/7
- Price agreed before work starts
- Workmanship guaranteed
Monday – Sunday, 7:00 AM – 10:00 PM · Out-of-hours emergency? Call 020 3576 5825
Get a price for boiler repair
Three details get an engineer moving. The rest is optional.
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What this includes
- Breakdown diagnosis and fault finding
- Boilers locked out on a fault code
- No heating or no hot water
- Central heating and radiator faults
- Thermostats and heating controls
- Pressure loss and repeated refilling
Worth knowing first
A little of this might mean you do not need to call us at all — we would still rather you knew it.
Before you call, check three things
Three quick checks save a lot of callouts. Look at the pressure gauge — is it roughly between 1 and 1.5 bar? Is the thermostat actually asking for heat? And has the gas cut out elsewhere too, say on the hob? Low pressure and a stuck thermostat between them explain most of the breakdowns we get called out to, so it is worth ruling both out before you pick up the phone.
Fault codes are worth photographing
If your boiler is showing a code on its display, take a photo and send it on WhatsApp with the make and model. It often tells the engineer what part to bring, which is the difference between one visit and two.
Repair or replace
A boiler over about twelve years old, needing an expensive part, is usually worth replacing rather than repairing. Under that, a repair normally wins. We will give you both numbers and let you decide.
Pressure that keeps dropping
A boiler you have to refill every few weeks is losing water somewhere. That is a leak on the system or a failed expansion vessel, not something topping up will fix — and it is worth finding before it stains a ceiling.
What affects the price
A boiler repair is priced once the fault has been found, not before. Until the engineer has tested the boiler, nobody can honestly say which part has failed, and the part is what decides most of the cost.
Which part has failed
A pressure sensor, a thermistor or a condensate trap is a small part and a short job. A fan, a gas valve, a diverter valve or a printed circuit board costs considerably more, and a failed heat exchanger can push the repair past what the boiler is worth.
Whether the part is on the van
If the engineer has the right part with them, the boiler can often be running again on the same visit. A part specific to your model may need ordering, which means a second trip. Sending the make, model and fault code beforehand improves the odds.
The age and make of the boiler
Parts for current models from the big manufacturers are easy to find. Parts for older or less common boilers can be scarce and expensive, and for some there is no longer anything available at all, which turns a repair into a replacement conversation.
The boiler, or the system around it
Not every heating fault is inside the boiler. A seized pump, a sticking motorised valve, a dead room thermostat or sludge in the pipework can all stop the heating. Where the fault sits, and how easily it can be reached, changes the price.
The price is agreed before any work starts. We take card and cash.
Common questions
Is my boiler worth repairing?
It depends on age and the part that has failed. We will quote for both the repair and a replacement so you can compare the two honestly, rather than being told only one number.
My boiler is showing a fault code. What does it mean?
Codes differ by manufacturer, so we would rather see it than guess. Send a photo of the display with the make and model on WhatsApp and we can usually tell you what is likely before an engineer sets off.
Why does my boiler keep losing pressure?
Most often there is a leak on the system somewhere, or the expansion vessel has failed. Topping it up again and again just hides the symptom — it does not fix anything, and a slow leak sitting in a ceiling void turns into a much bigger bill the longer it runs.
Are your engineers Gas Safe registered?
Yes. Gas work is legally required to be carried out by a Gas Safe registered engineer, and ours are.
My boiler is still under the manufacturer’s warranty. Should I call you?
Call the manufacturer first. A boiler still under warranty is usually repaired by the manufacturer’s own engineers, and another company working on it can complicate a claim. Have the installation date and your service records ready, because most manufacturers ask for proof of annual servicing. If the warranty has run out, or the manufacturer will not cover the fault, we are happy to diagnose and repair it.
Is it safe to keep resetting the boiler when it locks out?
Pressing reset once or twice after a lockout is what the button is for. If it locks out again straight away, or keeps doing it day after day, stop resetting it — a lockout is the boiler protecting itself, and forcing it back on can make the fault worse. If you smell gas at any point, turn the supply off at the meter, open the windows and call the National Gas Emergency Service on 0800 111 999.
Boiler repair near you
Local pages for the areas where this comes up most.
- Boiler repair in Wimbledon
- Boiler repair in Ealing
- Boiler repair in Croydon
- Boiler repair in Harrow
- Boiler repair in Dulwich
- Boiler repair in Fulham
- Boiler repair in Wandsworth
- Boiler repair in Clapham
- Boiler repair in Bromley
- Boiler repair in Greenwich
- Boiler repair in Kensington
- Boiler repair in Walthamstow
- Boiler repair in Brixton
- Boiler repair in Chelsea
- Boiler repair in Battersea
- Boiler repair in Tooting
- Boiler repair in Guildford
- Boiler repair in Woking
- Boiler repair in Hackney
- Boiler repair in Hammersmith
- Boiler repair in Lewisham
- Boiler repair in Putney
- Boiler repair in Acton
Related appliance work
These installations sit under this service, and each has its own page covering what is involved.
-
Immersion Heater Replacement
The electric element in the hot water cylinder — replaced when it fails, and checked before anyone talks about a new cylinder.
More on immersion heater replacement
More heating work we take on
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Boiler Service
The annual check that keeps a boiler safe, efficient and inside its warranty terms.
More on Boiler Service -
Boiler Installation
A new boiler sized for the property, fitted properly, with the price agreed first.
More on Boiler Installation -
Boiler Replacement
Replacing a boiler that has reached the end, with a straight answer on whether it has.
More on Boiler Replacement -
Central Heating Installation
The whole system — boiler, pipework, radiators and controls — rather than a new boiler on its own.
More on Central Heating Installation
Looking for a specific make?
Every brand gets its own page on what is typical of it and the faults that tend to come up on that make.
Need boiler repair in London?
Describe the problem and give us your area, and we’ll tell you the price before anyone starts work.