My flat has nowhere to put a normal boiler flue. Is that solvable?

Often yes, and this is exactly the case twin-flue systems exist for. They allow far longer flue runs than a standard boiler, so a unit can go somewhere a conventional flue could never reach. It needs designing properly rather than improvising, and we would look at the path the flue would take before recommending it.

Why does my boiler flue need inspection hatches?

So the whole flue can be seen and confirmed sound. In a block of flats, the managing agent or freeholder may need to approve work to ceilings or communal areas, so raise it early.

Can I replace my Keston with another brand?

Sometimes. It depends on whether another boiler’s flue can reach outside from where yours sits. In some flats the twin-pipe design is the only thing that makes a boiler possible at all.

Do you repair and service Keston boilers?

Yes. Gas work is carried out by Gas Safe registered engineers, which is the legal requirement for working on any gas boiler regardless of make.

Tier 2 · Gas, domestic and light commercial

Keston boiler repair and servicing in London

Twin-flue boilers that solve flue problems ordinary boilers cannot — particularly in London flats.

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Gas Safe registered and fully insured
Diagnosed before it is quoted
Price agreed before work starts
Workmanship guaranteed

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About the brand

Keston boilers

Keston solves a problem that is particularly common in London. Its twin-flue design allows much longer flue runs than usual, which makes installation possible in flats and buildings where the boiler sits nowhere near an external wall and a conventional flue could never reach it. In high-rise and deep-plan conversions, that is sometimes the difference between Ninja Plumbers finding a workable installation and having none at all.

The Keston range

Keston is a British brand built around one idea: a condensing boiler whose flue uses two small plastic pipes, one for air in and one for exhaust out. That flue can run much further, round more bends, than a standard one. Keston makes combi, system and heat-only boilers, plus larger light commercial models, and many London Kestons sit in blocks and deep conversions with flues through ceiling voids.

What we see on Keston boilers

Long flue runs in flats where the boiler sits far from any external wall
High-rise and deep-plan properties where the flue has few places to go
Condensate arrangements over long runs needing careful design
Flues concealed in ceiling voids with no inspection hatches
Roof and high-wall terminals that need planned access

These are patterns Ninja Plumbers sees across the Keston installed base, not a diagnosis of your boiler. Faults are identified on site before anything is quoted.

Servicing a Keston

The flue is what makes a Keston different to service. Both pipes are checked along their length, and industry guidance since 2013 says a flue hidden in a ceiling void needs inspection hatches; without them the installation can be classed "at risk". On newer models, check your warranty terms: they usually require an annual service. Tell us where the flue comes out when you book.

Repair or replace?

A Keston is often worth repairing for longer than most boilers, because replacing it is not always simple: if the flue only works thanks to the twin-pipe design, an ordinary boiler may not fit in the same place. When one does reach the end, the replacement needs designing before we quote, including whether the flue can be reused.

What we do

Keston boiler work

Keston boiler repair

Breakdowns diagnosed before anything is quoted.
Keston boiler service

The yearly check most manufacturer warranties ask for.
Keston boiler installation

Sized for the property, with the price agreed first.
Replacing a Keston boiler

Both figures — repair and replace — before you decide.

Questions

Keston questions

My flat has nowhere to put a normal boiler flue. Is that solvable?: Often yes, and this is exactly the case twin-flue systems exist for. They allow far longer flue runs than a standard boiler, so a unit can go somewhere a conventional flue could never reach. It needs designing properly rather than improvising, and we would look at the path the flue would take before recommending it.
Why does my boiler flue need inspection hatches?: So the whole flue can be seen and confirmed sound. In a block of flats, the managing agent or freeholder may need to approve work to ceilings or communal areas, so raise it early.
Can I replace my Keston with another brand?: Sometimes. It depends on whether another boiler’s flue can reach outside from where yours sits. In some flats the twin-pipe design is the only thing that makes a boiler possible at all.
Do you repair and service Keston boilers?: Yes. Gas work is carried out by Gas Safe registered engineers, which is the legal requirement for working on any gas boiler regardless of make.

Other brands

We work on every make

Something wrong with your Keston?

Send us the model and any fault code showing on the display, and we can often tell you what is likely wrong with it before an engineer sets off.