Boiler and gas engineers in London
Whatever the make and whatever the problem, our Gas Safe registered engineers repair, service, install and replace gas boilers across London. Every engineer is directly employed, DBS-checked and insured, and you get a price before any work starts. Pick what is happening from the list below, or send the make, model and fault code, if there is one, and we will tell you the likely problem before anyone sets off.
- Fully insured and Gas Safe registered
- Engineers who are DBS-checked
- 24/7 emergency callouts on offer
- You agree the price before we start
- Our workmanship is guaranteed
Monday – Sunday, 7:00 AM – 10:00 PM · Out-of-hours emergency? Call 020 3576 5825
Tell us about the boiler
Name, phone and postcode are all we need to start. Everything else can wait.
Thank you — your enquiry is in
Expect a call back on the number you entered. For anything urgent, there is no need to wait: ring 020 3576 5825.
What's happening with the boiler?
Pick the closest match and go straight to the page that deals with it.
- The boiler has stopped or shows a fault code Diagnosis first, then a straight answer on the repair.
- Heating works, but the taps run cold Usually a diverter valve, sensor or cylinder control.
- The pressure keeps dropping A leak or a flat expansion vessel. Topping up only hides it.
- It works, but it has not been serviced this year Catches wear early and keeps the warranty conditions met.
- It is old and keeps breaking down Repair or replace, with both options costed side by side.
- You need a boiler where there is none New installations, including a change of boiler type.
- Landlord needing a gas safety record The yearly CP12 check for rented homes.
- Radiators cold at the bottom Sludge in the system. A flush clears it.
Four separate jobs
Each job has its own answer, so we give each one a page of its own rather than grouping them together.
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Boiler Repair
Heating off, hot water gone or a fault code on the display. We find the cause, then fix it.
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Boiler Service
A yearly check to keep your boiler safe, running efficiently and covered by its warranty.
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Boiler Installation
Your new boiler, matched to the size of the home, installed well, at a price agreed up front.
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Boiler Replacement
A new boiler when the old one is finished, and an honest view on whether it really is.
Which boiler do you have?
Most London homes have one of three types. A combi heats water the moment you open a tap, with no tank anywhere, and is what you will find in most flats and many terraced houses. A system boiler heats a hot water cylinder, usually in an airing cupboard, and suits homes with more than one bathroom. A regular, or heat-only, boiler works with a cylinder and a cold water tank in the loft, and is common in larger period houses that have not been converted. Knowing which you have helps us work out what has gone wrong before we arrive, and it matters when you replace one, because swapping type changes the pipework.
Repair, service or replace: how we decide
The engineer finds the fault before anyone talks about a new boiler. Most breakdowns come down to one part, such as a fan, a diverter valve, a sensor or a pump, and fixing it is the sensible answer. Replacement makes sense when the same boiler keeps failing, when parts for it are hard to get, or when a major part such as the heat exchanger has gone on an older unit. When it is a close call we give you the repair cost and the replacement cost side by side and leave the decision with you. A yearly service is the cheapest way to stay out of that position in the first place.
Boilers in London homes
London throws up the same boiler problems again and again. Converted flats often have the boiler in a kitchen cupboard with a flue that has to meet clearance rules from windows and neighbouring properties. Hard water leaves scale in combi heat exchangers, which shows up as lukewarm or fluctuating hot water. Condensate pipes that run outside freeze in a cold snap and lock the boiler out. Older houses can still have gravity-fed systems full of sludge, which starves radiators and strains a new boiler if it is not flushed out first. These come up all the time in London homes, so our engineers know what to look for.
Gas Safe and the paperwork
By law, anyone working on a gas boiler in a home must be on the Gas Safe Register, and you can check an engineer by the number on their ID card. A new boiler installation also has to be notified to building control. A Gas Safe registered installer does that for you, and you receive a Building Regulations compliance certificate afterwards. Manufacturer warranties usually depend on the boiler being registered after installation and serviced every year, so keep the service records. Landlords must have gas appliances checked every year and give tenants a copy of the gas safety record.
What affects the price
We agree the price before any work starts, and it depends on the job. For a repair, the main factors are the part that has failed, whether it is in stock for your make and model, and how easy the boiler is to reach. For a replacement, it is the type and size of boiler your home needs, whether it goes in the same place, any changes to the flue, gas pipe or condensate route, and whether the system needs flushing first. If you give us the make and model, plus any fault code, when you first get in touch, we can give you a clearer idea from the start.
The makes we cover
The law lets any Gas Safe registered engineer work on every make. Each page below explains what is typical of that brand and which faults tend to appear.
- Worcester Bosch
- Vaillant
- Ideal Heating
- Baxi
- Viessmann
- Glow-worm
- Alpha Heating Innovation
- Vokèra
- Intergas
- ATAG
- Ariston
- Ferroli
- Navien
- Potterton
- Keston
- Biasi
- Ravenheat
Brands that are legacy or transitioning
Plenty are still fitted in homes, though buying one new is not simple. We service and repair them and advise on the right replacement.
Things to know before calling
Will you work on any make of boiler?
Yes. The law allows any Gas Safe registered engineer to work on any make of gas boiler. When a brand is no longer sold new, the badge is not the problem; finding parts is.
Are you approved by any boiler manufacturer?
We make no claim to manufacturer accreditation. Our gas work is done by Gas Safe registered engineers, which is what the law requires, and we would sooner tell you what we hold than hint at something we do not.
How often does a boiler need servicing?
Every year. For most manufacturers an annual service is a warranty condition, and it is when worn seals, a blocked condensate trap or a part on its way out get spotted before they stop the boiler in winter.
My boiler is still under the manufacturer’s warranty. Should I call you?
Ring the manufacturer first. A repair by anyone other than their own engineers can affect the warranty, and the repair itself may be free. We can still carry out the yearly service, which is what keeps most warranties valid in the first place.
What should I have ready when I get in touch?
The make and model (usually on a label on the front or underneath), any fault code on the display, the reading on the pressure gauge, and whether you still have heating, hot water or neither. A photo of the display on WhatsApp is often enough for us to narrow it down.
What should I do if I smell gas?
Turn off the gas at the meter if you can safely reach it, open doors and windows, do not use light switches or anything that could spark, and call the National Gas Emergency Service on 0800 111 999. Once they have made it safe, we can find and repair the fault.
Do you work on oil or LPG boilers?
No. We work on mains gas boilers only. Oil boilers need an OFTEC-registered engineer, and we would rather point you to the right trade than take on work outside what we do every day.
More help: no hot water, low boiler pressure and landlord gas safety certificates on our blog, or the wider heating services page.
Trouble with your boiler?
Send Ninja Plumbers the make, the model and whatever fault code is on the display. Often we can work out the likely cause before an engineer has left the office.