This week, we’ve been working in Brixton, in South London, in a converted factory building close to a windmill.

The Brixton Windmill on a bleak, overcast and persistently raining day.

I’ve been to Brixton countless times, and although I appreciate it is a trendy area, I never realised they had a full sized windmill.  If you want to know more about the Brixton Windmill (or don’t believe there is a Windmill in Brixton) see here.

The factory was converted in around 2003, and each unit was designed differently inside.

Our van blocking the car park

With 4m high ceilings, enormous glass brick windows and concrete screeded floors, this is an amazing, unique property conversion.

This staircase rises through 3 floors and around 12 metres

It is home to Russell James, otherwise known as The Raw Chef.  From here he creates exciting new recipes, and develops courses in raw food cooking, to share with over 43,000 followers across the World.  And, let me tell you, as well as being lauded by The Times, he is a really nice chap.

Anyway, you are probably wondering what this has got to do with hot water and central heating.  So here’s the list of problems and how we solved them.

Firstly, and this is a familiar thread, a Keston C40 boiler had been installed on the party wall.  Although the party walls were strongly constructed, a Keston C40 is a very noisy thing, so the neighbours could hear it.  The boiler was then moved forward and 3″ of Kingspan insulation placed behind it, but from all accounts this made little difference.  Architects love Keston boilers because you can site them anywhere…… as long as no one is sleeping nearby.  And then, of course, there’s the unreliability of the thing.  In our experience, you’ve done well with any of these if they see longer than 24 months between breakdowns.

Old Keston C40 complete with safety warning label

There was an unvented hot water cylinder, but that had also been installed incorrectly, was therefore dangerous, and being a glass lined steel unit with a failed cathodic protection system, it was leaking.  So it needed to be changed.

And finally, the water boosting system.   Because the height of the building was around 12 metres, the developer had found that the water pressure gave an almost useless shower on the 2nd floor.  So he retrospectively added a couple of huge water storage tanks in a loft space, and a Grundfos whole house booster pump.  If he had involved us then we would have argued against this solution…..

This is the Grundfos whole house pump, it is around 2 feet long.

Two large water tanks with pump in background. All of this equipment has been removed.

The Keston boiler now had a real challenger on the noise stakes, because a Grundfos break tank booster pump is not a quiet thing.  Various contractors had tried to quieten the uniit, as it was sitting on a concrete slab, and then had been boxed inside an MDF box.  Shame they didn’t fit an overflow pipe to the tanks, because this was identified some years later when the break tanks overflowed.  Being a break tank, the pump runs every time a tap is opened, or a toilet is flushed.  Or sometimes just a small drop of pressure in the pipe starts it up for a second or two in the middle of the night.

It all had to go.  Boiler, cylinder, break tanks and pump.

We’ve got 4 days to fit all this…… No cooking in this area for a few days

We recommended fitting one of our accumulators and a pump charger to replace all the break tank equipment;  this was resited in a utility area under the stairs on the ground floor.

This is the understairs area in the utility room before…

New water boosting system finished

Close up of Charger for accumulator


The Accumulator and Charger boost the water pressure to 3bar (in this installation) and fill the accumulator with around 220 litres of pre pressurised water.  A substantial amount of water can be drawn off before the Charger pump starts, and because it is electronically limited to pumping in just 12 litres per minute into the accumulator, is both quiet in operation and is allowed to be connected direct to the water main. Flowrates from the new system are easily the match of the old, without the noise!  And the water supply is still available in a power cut.

We removed the Keston, which had already been disconnected by another contractor due to a cracked plastic flue, so the house was really cold. Although the Keston was a 40Kw unit, our heating calculation suggested a 25Kw boiler would be more suitable, so we fitted a new Worcester-Bosch 30Kw system boiler.  The gas supply pipework was significantly undersized for the 40Kw boiler, and by calculation it would have been insufficient even for a 30Kw unit, so the sizing was changed and the pipe rerouted to minimise bends.

The unvented cylinder was changed for a new Ariston Aquabravo stainless steel unit, which was chosen because it was one of the few units that was dimensionally suitable for the cupboard.  Unlike the previous unit, all the discharge pipework was correctly installed and terminated at ground level.

The system was Powerflushed and Magnacleansed, to remove the most debris currently achievable.  A Worcester Bosch system filter was fitted to the boiler to catch any further contamination, and to extend the boiler warranty by an additional year.

Finished Worcester-Bosch 30CDi Greenstar System boiler and unvented HW cylinder (loose black cables are Sky TV, not ours!)

As a Gold Tier Worcester Bosch installer we get special terms on customer warranty, and unlike many other manufacturers, it is Worcester-Bosch, not an insurance company subcontractor that expedites any repairs.

The boiler was warranted by the manufacturer for 8 years;  to 2022 in fact.

This job was a result of a recommendation from the owner’s mother, for whom we carried out a large boiler renewal job last year.