There is nowhere in my flat for a normal boiler flue. Can that be solved?

Often it can, and it is the very situation twin-flue systems were made for. Their flues can run much further than a standard boiler’s, so the boiler can sit where an ordinary flue would never reach the outside. It has to be designed properly, not improvised, and we would study the route the flue would take before recommending it.

Why does my flue need inspection hatches?

So the full length of the flue can be seen and checked as sound. In a block of flats, the managing agent or freeholder may have to approve work to ceilings or shared areas, so bring it up early.

Could I replace my Keston with a different make?

Sometimes. It depends on whether another boiler’s flue could get outside from where yours is. In some flats, only the twin-pipe design makes a boiler possible at all.

Can you repair and service my Keston boiler?

Yes. Our gas work is done by Gas Safe registered engineers, as the law requires for any gas boiler, whatever the make.

Tier 2 · Gas, domestic and light commercial

Keston boiler repair and service engineers in London

Boilers with a twin flue that get round flue problems a standard boiler cannot, especially in London flats.

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Every fault diagnosed before we quote
You agree the price before we start
Our workmanship is guaranteed

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The make

Keston boilers

Keston deals with a problem London has more than most places. Thanks to its twin-flue design, the flue can run far further than normal, so a boiler can go into flats and buildings where it sits well away from any outside wall and an ordinary flue would never get out. In tall blocks and deep-plan conversions, that can decide whether Ninja Plumbers finds a workable installation 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.

Faults we often find on Keston boilers

Flats needing long flue runs because the boiler sits well away from an outside wall
Tall blocks and deep-plan buildings where the flue has few routes out
Condensate drainage over long runs that needs careful design
Flues hidden in ceiling voids with no inspection hatches
Roof and high-wall terminals that need access planned

This list reflects what Ninja Plumbers finds across Keston boilers in general. It is not a diagnosis of yours, and we confirm any fault on site before giving a price.

Keston servicing

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 it or replace it?

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.

Our services

Work we do on Keston boilers

Keston boiler repair

We find the fault first, then quote for the fix.
Keston boiler service

An annual check, which most manufacturer warranties require.
Keston boiler installation

Matched to your home, at a price agreed up front.
Keston boiler replacement

You see repair and replacement costs side by side first.

FAQs

Questions about Keston boilers

There is nowhere in my flat for a normal boiler flue. Can that be solved?: Often it can, and it is the very situation twin-flue systems were made for. Their flues can run much further than a standard boiler’s, so the boiler can sit where an ordinary flue would never reach the outside. It has to be designed properly, not improvised, and we would study the route the flue would take before recommending it.
Why does my flue need inspection hatches?: So the full length of the flue can be seen and checked as sound. In a block of flats, the managing agent or freeholder may have to approve work to ceilings or shared areas, so bring it up early.
Could I replace my Keston with a different make?: Sometimes. It depends on whether another boiler’s flue could get outside from where yours is. In some flats, only the twin-pipe design makes a boiler possible at all.
Can you repair and service my Keston boiler?: Yes. Our gas work is done by Gas Safe registered engineers, as the law requires for any gas boiler, whatever the make.

More makes

We handle every make of boiler

Problem with your Keston?

Tell us the model and whatever fault code the display shows. We can often say what the likely problem is before an engineer is on the way.

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