Over to the picturesque Sussex town of Horsham, where we have a beautiful listed residence in the protected heritage quarter of the town.

Green door in Horsham

British Gas condemned the old floorstanding Potterton boiler in the cellar, and they and other contractors suggested that the only solution was the relocation of a new boiler at the other end of the house, involving unsightly pipework throughout.

The existing defunct boiler was flued up a very old chimney weaving through 3 floors; we suggested fitting a new Viessmann Compact 26Kw boiler in the cellar.  The existing system was very old, the cylinder was around 60 years old and the radiators were in their 40s, we estimate.

The system was fully Powerflushed and we converted the gravity system to a fully pumped type, retaining most of the original parts at the customer’s request.

Not a straight or flat wall in sight

The roof of the house was made of stone tiles, possibly York stone, and looked very old and possibly fragile.  Rather than use scaffolding, which would rest on the roof, we suggested a truck mounted access hoist was employed.  We’ve used these in the past and they can offer quick and easy access to some difficult areas without even touching the fabric of the building.

Easy with the right equipment - and a head for heights

The new flue was inserted, and the boiler converted to an ‘open flue’ type, where air is used in the cellar for combustion.

View from the top

Our brief was to keep all the radiators, hot water cylinder etc as before, so some very old pipework remained in the cellar, which we added insulation.

Parking restrictions were everywhere, but Horsham council run a very efficient dispensation scheme for contractors working on these period properties.

Getting the old boiler out of the cellar, this was the easy bit

We left the house with a brand new condensing boiler, but (excluding the cellar) the house looked exactly the same as when we started.

Architect designed house in reigate

This property had an old HarcoPak, which is an integrated hot water cylinder and cold water storage tank, mounted in a frame on the 1st floor.

It was heated by an old Potterton Kingfisher 100BF floorstanding boiler, which had been installed with a flue a couple of inches from the rear door and an undersized gas pipe;  both of which were contrary to the gas regs at the time the house was constructed, and still are.

We removed the Potty boiler, leaving a large hole for the on site building team of Mizon Builders to brick up.

Old boiler position

We relocated the new boiler into the garage at the other end of the building.  We suggested a Worcester-Bosch 30CDi conventional.  This is a 102,000BTu boiler based on a Junkers design (a German part of the Bosch Group), a rugged wall hung boiler compatible with UK open vented radiator systems. 

New Worcester 30CDi in the garage

Due to the proximity of the neighbouring property at this point in the building, we proposed a vertical flue solution, and our customer was happy to agree.  We used the services of our professional roofing subcontractor, to make the aperture and weatherseal the flue terminal.  We always use our skilled roofing specialists because the work has to last the lifetime of the roof.

New vertical chimney outlet

Next, the hot and cold water.  We converted the systems to an unvented cylinder, where water is at mains pressure to all outlets.  Wherever possible it is best to site the hot water storage where there is a relatively short pipe run to most points of use, so the original airing cupboard was retained and a new 300 litre cylinder shoehorned in.

In 2011 the UK Government are committed to provide ‘feed in tariffs’ for solar generated hot water.  This means the end of cash grants towards the installation of solar hot water, but heralds the beginning of an annual rebate for new, accredited solar installations (it isn’t retrospective).  In preparation for this, we installed an unvented cylinder that has a solar coil – making the addition of solar panels much simpler at a later date.

Range Tribune HE Solar unvented HW cylinder

The Range Tribune HE Solar is a well made unit from the Kingspan Group, which is very similar to the Worcester-Bosch branded Greenskies unvented unit.   It is reasonably common knowledge that they all come from Kingspan, the ones for Worcester get silver paint. 

On to the underfloor heating.  Our customer had a large conservatory area, and a kitchen and utility into which he rather liked the idea of installing underfloor heating.  The problem he had was the finished floor level; using conventional water underfloor heating the floor level is typically going to rise by around 75mm.  The alternative is an electric blanket – these are cheap to buy, cheap to fit, and around 300% more expensive to run than a gas fired UFH system.  Also, if the small element fails, digging the floor up is the only option.

As the floor already had insulation fitted when the building was constructed around 17 yrs ago, we specified the Velta MiniTEC system.  This unique underfloor system uses a 9.9mm pipe and a special polymer screed system, resulting in a floor uplift of only 15mm.

Velta miniTEC - and a 2p coin for scale

The floor is levelled and then a plastic castellated support sheet is glued to the floor.

MiniTEC being laid

Over a period of a few hours the rest of the support system was laid and the pipework grid overlaid.

Underfloor nearly finished

The existing radiators were prepared by Powerflushing, and separate heating zones set up to enable timed, programmable temperature areas.

Most of the new pipework was conveniently hidden and insulated within voids in the eaves.  A 28mm water supply pipe was installed for the new unvented cylinder supply, to obtain the best performance from the existing water main.

8 days later the works were completed, I look forward to seeing the finished kitchen area!

St John the Evangelist, Hildenborough

Our photo shows Dan in contemplation, in the graveyard of St John the Evangelist, in Hildenborough, Kent.  Actually, he’s assisting in a purging operation at the gas meter box.

This church, constructed over 100 years ago, was heated by an old 86kW Ideal Buccaneer commercial boiler.  The boiler had a reputation for breaking down in the hour of need (eg: coldest days of winter) and the management team had found the only way to minimise the chances of failure was to have the boiler on in periods of the summer.

Old Buccaneer boiler

The heating was controlled by a bewildering set of high/low thermostats and timeswitches, and it wasn’t clear to any of the users what, if any, effect they had on the heating.  Large gas bills were being incurred all year round, and the church treasurer concluded that the sooner a solution was found, the earlier savings could begin.

The church management committee wanted a new system, preferably a high efficiency condensing replacement.  The church has a listed exterior, and the boiler plant is in the basement, with a restricted ceiling height.

Interior view of St John the Evangelist

The job was put out to tender;  Hot Water & Central Heating were the only company to propose a modern high efficiency solution.  We suggested a Viessmann Vitocrossal 200 series, which would be a reasonable fit in the congested boiler room, and importantly, it has a very low level flue outlet.  The boiler has an efficiency in excess of 90%, and is exceptionally quiet in operation.

The flue system in a condensing boiler installation requires non corrosive materials, typically stainless steel or plastic in construction.  The system we chose for this job was a Viessmann product, made by Skoberne, and consisted of 150mm diameter plastics sections.  Running the flue outside was not possible due to the aesthetics, so we devised a way of using the old chimney annulus for the majority of the route, with a small break in point in the church to facilitate a swept bend.

This was the only visible works, later boxed in

The old cast iron boiler was broken up and removed.  The opportunity was taken to renew the lighting in the boiler room with 4×55w fluorescent weatherproof battens, which was part of our quotation – as the 60watt bulb was not very effective in a black room.

Part of the old boiler awaiting the scrap contractor

We arranged for scaffolding to be put up around the chimney, as it is over 35feet high, and the installation proceeded apace.

Rick Johnson, our brick maestro subcontractor

The new boiler was installed, together with new pumps and controls.

Vitocrossal 200 stainless steel heat exchanger

We altered the layout of the steel threaded pipework and the gas supply;  the Viessmann Matrix burner and casings were fitted, together with the integrated Vitotrol 100 controls.

Nearly finished!

 Finally, the rooftop work was completed and the scaffolding removed.

Finished chimney termination

The last bit is how the church’s many users will control the heating.  We’ve configured the boiler to work with a standard domestic Honeywell programmable room thermostat.  This will enable the management team to preprogramme temperature levels for the week, keeping the building on a low level heat when unoccupied and at comfortable levels when in use.

Honeywell programmable thermostat

Temperature settings can easily be overriden by church users, but any changes made are temporary – the CM927 we have used will be familiar to many as the easiest to use temperature control currently available.

Many building services engineers fit complex heating controls, but in multi-occupancy buildings there is often no permanently employed person to manage the system, and it is effectively running out of control.  We believe in making things as simple as possible, this is the only way comfort and efficiency can exist together. 

The Viessmann Vitocrossal is a premium product, superbly engineered, and should last many years in this application, whilst reducing energy usage by over 30%.

Large loft extension underway, temporary roof being installed

The house pictured, located in Croydon, Surrey UK,  was being extended into the loft space.  The loft tanks for the hot water system and radiator header tanks had to be removed to make way for the new accommodation.

Our challenge was to provide a new heating and high pressure cold & hot water system in an 1900mm high cellar, which could replicate the shower performance of the existing powerful pumped tank fed system in the loft.  Furthermore, it should support the use of extra bathrooms in the loft area.

This project raised a number of challenging problems.  We could have fitted an unvented hot water cylinder in the basement but there were height constraints limiting the capacity, and no drainage. 

Unvented cylinders require an emergency discharge which must run downhill.  In the event of an over-pressure or over-temperature situation developing, a valve lifts discharging very hot water at mains pressure.  Clearly this was impossible in a cellar. 

The unvented regulations hint that in extreme circumstances, a metal catchment tank could be fitted in a cellar, together with a suitably rated submersible pump.   Problem is, the water could be discharged at 85C and there aren’t suitable submersible pumpsets available rated to keep working at this high temperature.  Furthermore, after many years of potential inactivity the pump could fail to operate at the critical day and then the cellar would flood.  So this was not a practical option.

DPS Pandora Heatstore

Instead, we looked at a heatstore solution.  This is a large vat of water contained in a shell, which in our case is indirectly heated by the boiler.  The water in the heatstore never changes, it is used purely as an energy storage media.  When hot water is required, a 100Kw rated plate heat exchanger is used via a simple pump to transfer heat into the cold main, instantaneously.

We specified a heatstore from Dedicated Pressure Systems, the recognised experts in this field, and based nearby to Hot Water & Central Heating in Epsom, Surrey.   The DPS Pandora was specified in a custom built configuration to just fit below the ceiling in the cellar and pass down the stairway.  DPS’s Pandora is unique becasue it does not require an overflow connection – which makes it ideal for our location.

Mainsboost accumulator upgrades mains water supply

To ensure the DPS Pandora could achieve the design hot water flowrate, we used a TCWS Mainsboost GC450 accumulator to boost the water supply within the property to a flow rate far superior to that provided by Thames Water.

The nett result is a fantastic shower performance which is somewhat akin to a pressure washer.  Indeed, our technical team inadvertently dropped the mobile shower head and got soaked trying to chase it around the bath.  It then slipped out of our hand and we got a second soaking;  a few choice words were exchanged.

We also had to remove an old balanced flue Potterton boiler from the utility room and fit a new high efficiency Vaillant ecoTEC 637 condensing boiler in the cellar.

New Vaillant 637 and zoning system pipework in cellar

As most boiler installers will tell you, fitting a boiler in a cellar leads to flue problems.  If we had fitted a flue to outside from within the cellar height, it would have appeared in the alley outside just 50mm from the ground level.  This is not permitted because the air inlet could be blocked by leaves in the autumn or snow in the winter (although we still see some fitted in this way) leading to a potentially dangerous situation.  We have seen dropped wells dug into the outside garden but these too do not meet regulations unless they are very large indeed.

Neat flue installation from downstairs cellar

We overcame this problem by extending the flue upwards  into the kitchen, by adapting the rear of an existing kitchen unit.  We removed the unit carefully from under the marble worktop and cut a suitable aperture in the rear, and then reassembled the unit around the flue.  This now discharged outside horizontally at an acceptable height of around 450mm from ground level.

Due to the proximity of the adjacent property, we fitted a neat Vaillant plume management kit (PMK) in black, which took the steam to a height of around 6 metres.

Plume management kit was employed to lift boiler steam to 6m high and direct it away from the neighbouring property

Finally, there was the problem of converting the existing central heating system over to a sealed type using expansion vessels instead of the old loft feed and expansion tank.

On the face of it, this is easy, but once again, the emergency pressure relief pipework is not allowed to pass through a vertical element (in case it gets blocked/ freezes).  And due to the absence of drainage in the cellar, dumping the expansion relief on the floor does not meet good practice or building regulations.

Emergency catchment tank

We approached this problem with two solutions.  Firstly, we fitted a galvanised 180 litre catch tank on the basement floor, so that if the 3 bar expansion relief valve did open inside the boiler, all the potential water in the heating system could be safely contained.

But this would be inconvenient to the homeowner if the tank filled, so we fitted an additional expansion relief valve downrated to 2.5 bar just above ground level to discharge conveniently outside.  In this way, the outside valve should lift before the boiler valve in a fault situation, preventing the catchment tank from ever being used. 

A spare plumbed zone valve bay was left in the cellar for a potential future conservatory extension with underfloor heating, and the existing heating system was divided into two zones with individual Honeywell CM927 radio linked programmable room thermostats.

So all in all, quite an involved job, but completed as per our detailed quotation, and delivered on time.   As usual, our Vaillant boiler installation is backed by a 5 yr parts and labour warranty.

Rust, Rust and Rust

The Energysaver was one of Glowworm’s early efforts at a high efficiency boiler.  Like the ill fated Potterton Envoy and Baxi Barcelona, the Energysaver had the lifespan of a prawn sandwich.    Although manufacturers like Archie Kidd had perfected the art of condensing boilers decades earlier, the mass market British boiler industry left their designs to the last minute and used their loyal customer base as a test bed. 

Glowworm was snapped up by Vaillant (a leading German boiler manufacturer) over 5 years ago and the Energysaver model was quickly consigned to history and replaced by European designs.  Meanwhile, 5 or 6 years seems to be about the average lifespan before serious internal deterioration renders an Energysaver beyond economic repair.  A classic example of how ‘Green’ labelled products do not necessarily save the planet.

We now travel to Oxted Surrey, where we had been asked to provide a recommendation for a new boiler.

House in Oxted

Our customer had such a boiler and it was leaking.  Being in no mood to buy another boiler with a short lifespan, and due to the tight location within a kitchen unit, we suggested that a Worcester Ri series replacement would prove more reliable and long lived. 

New boiler in position

As usual, we provided a 5yr parts and labour warranty on the unit, and the primary component (heat exchanger) is covered by Bosch for 10 years.  Their only stipulation is that the boiler should be annually serviced.

Working on behalf of a Landlord, we replaced a 20yr old Vaillant system boiler in this apartment block in Peckham, South East London.

Peckham apartment block

The old unit was beyond economic repair, and our customer wanted the peace of mind a new boiler with a 5 year warranty would bring.  We imagine his tenant would be appreciative too.

We removed the old unit, powerflushed all the radiators, and dosed the system with corrosion inhibitor. 

Powerflush machine pressed into service as a WorkMate

Nearly finished, the old wooden pipework cover fitted

When we connected the new boiler there were problems with the hot water motorised valve in the upstairs airing cupboard.  Upon examination the wiring and and the valve were suspiciously new;  it turned out that the owner had paid a plumber and an electrician a not inconsiderable amout of money to diagnose and fix a fault earlier this year, and they had made some elementary wiring errors……this took us another hour to rectify.  But we like controls wiring jobs, haven’t found one we can’t fix yet.

The flue needed to pass under an external balcony;  we modified the old boxing to accommodate the new flue.

New flue arrangement

The old system had no room thermostat and relied on radiator valves with thermostatic heads.  This is no longer permitted when a new boiler is fitted*, because the boiler continues to fire regularly even when the rooms are up to temperature, wasting fuel.  We fitted a Honeywell programmable room thermostat, with a 7 day programme.

*to be pedantic, there is an exception for a boiler with an integral heating flow switch, such as one of the Baxi models.

Having installed a Vaillant boiler in a rented property owned by this customer in 2008, we were invited to quote for a new boiler in his main residence, a very nice house near Hurstpierpoint, Sussex, UK.

This house has a smaller gas bill than before

We recommended the Vaillant 428 ecoTEC+ compact heat only boiler.  This manufacturer has a unique selling point in that their external flue can be routed to a vertical termination point. 

New Vaillant ecoTEC+ 428 (existing timer retained by customer)

Many condensing boiler installations have a nuisance factor in that the steam (or ‘plume’ as we describe it) passes visibly across the house and can be detrimental to the owner’s enjoyment.  The Vaillant flue system can use a small white or black pipe that can, in most cases, run to eaves level to discharge the steam vertically.  This is what we specified at this house.

Flue discharges next to gutter top right

The gas main to the old boiler was also feeding an AGA and a working pressure reading found the boiler to be grossly under supplied.  A new, larger pipe was going to be needed;  in fact, the previous installer of the boiler should have spotted this;  but regulations were not as tightly enforced 20 years ago.  It was not desirable to lift some fitted flooring in the kitchen, so with the approval of the customer we ran a new gas main through a store area and then at low level around the outside of the house to the new boiler. 

The new gas pipe was hidden where possible

Our customer was pleased with the flue arrangements and can now look forward to saving some of his gas bill (the AGA will continue to use vast amounts!) and having the peace of mind provided by the 5yr parts and labour boiler warranty.

Quieter, smaller, more efficient and warranted for 5 yrs until 2014.  A new Vaillant ecoTEC boiler has a lot going for it when installed by Hot Water & Central Heating!

Worcester Bosch have recently brought out a new range of floor standing boilers.  Designed to replace the inefficient Potterton Kingfisher, Ideal Mexico and other floor standing boilers of old, this new unit looks similar, and in most situations can be fitted directly in place of the original.

Our customer lived in a large house in Banstead, Surrey.  Being a retired doctor of engineering,  he knew his old 125,000 BTu Potterton Kingfisher was not going to last much longer, and rather liked the idea of swapping a 65% efficient boiler for a 91% efficient one.

New Worcester FS42 CDi during installation

He especially liked the idea of not having to relocate the boiler, or being told that a wall hung unit was the only viable option.

We recommended the new Worcester Greenstar FS42CDi, FS being short for floorstanding.  The new boiler is slightly more powerful than the old unit, but still uses less gas at full power, such is the value of condensing high efficiency Band A boilers.

We found that the gas supply from the meter was significantly undersized for the old boiler, suggesting it had never reached full output.  As a Gas Safe Registered business, Hot Water and Central Heating had to replace the gas supply pipe from the other end of the house with a new larger diameter copper pipe.

The flue arrangements for the old boiler involved a large 8″ vertical pipe passing through a single storey pitched roof and then running up the side of the building.  We proposed removing this and fitting a new room sealed flue system in a different position on the pitched roof.

Our roofer moving the flue outlets

Our partner roofing company made an excellent job of removing the old vertical flue equipment, sealing the old hole with matching tiles and creating a new outlet slightly further down the pitched roof, to meet Worcester Bosch exhaust distance requirements.

Old flue laid to rest

Our work also involved replacing and relocating some radiators in the hall area with our favourite Vogel & Noot panel radiators.

As per usual, the system was comprehensively Powerflushed and then dosed with Fernox F1 corrosion inhibitor.

Our customer was given a 5 year warranty on the new Worcester boiler, covering all parts and labour until 2014.

Finally, we received a glowing recommendation from the customer;

“We are pleased with the boiler and once again I repeat how I appreciated the quality of Tim’s plumbing work.  We will be happy to recommend your company to family and friends.  Do feel free to use this recommendation freely because as I said to you, I am very critical of the work of most of the tradesman that have worked in my house, so it is rather rare for me to be willing to recommend someone so freely”.   Dr W.

Limpsfield is a village on the outskirts of Oxted, Surrey (UK).

View from the road

Our customer already has a ‘Hot Water & Central Heating’ installed oil fired cooker range (see our Heritage cooker page above), and was building an outside barn further down the garden.

The central heating boiler was an old oil fired unit, which was located in the hallway and could be heard throughout the property.

Our customer wanted a new boiler and also wished to convert the water system to a new unvented type.

Hot Water & Central Heating suggested that a Grant 3646 outdoor module was fitted, this is an outdoor boiler incorporating a weatherproof housing, designed to operate outside in all weathers. 

Grant Vortex condensing high efficiency outdoor boiler module

This freed up the cupboard in the hall, previously home to an oil boiler and a small vented hot water cylinder on braces above.  We removed these units and replaced them with a Range Tribune Slimline 210 litre unvented cylinder.  This upgraded the hot and cold water to mains pressure at all outlets, and removed the need for a loft mounted storage tank.

Range Tribune unvented installation in cupboard

In common with all unvented systems (and other forms of direct fed hot and cold water systems, like combination boilers and heatstores) the performance is greatly improved with a good water flow rate.  We ran a new 32mm water pipe to the road outside, for minimum hydraulic resistance.   The local water supply company were engaged to provide a new larger connection to the mains.

New water connection being excavated by Sutton & East Surrey Water

The new oak barn was home to a sun room, together with a utility room and shower room.  Hot Water & Central Heating installed underground pipe ducts to the main house to give hot and cold services, and also to feed the new underfloor heating.

New oak barn

Underfloor heating manifolds are quite large units, and it is prudent to site them where inspection and maintenance is easily carried out after the building works are complete.  This ruled out fitting the manifold under the sink or behind washing machines.  Instead, we installed a 7 zone L&K manifold in the ceiling void area above the utility room, hiding the pipework in a stud wall comprising part of the new shower enclosure.

Underfloor installation waiting for screed

The L&K system used nearly 500 metres of pipe, all laid on Building Regs compliant Quinn  insulation board.  The Underfloor Heating was laid in a day, and the concrete screeding completed the day after.  The flooring will be finished in tiling once the screed has properly dried out.

Another view of the underfloor pipework

Heating manifold hidden in ceiling area

Screed laid, all pipework buried. This area will be tiled soon.

Separate zone controls were fitted for the underfloor area, which were linked by armoured cable buried in a duct to the existing house.  Control of the separate heating zones is by Honeywell CM series programmable room thermostats.

Underfloor heating is an invisible but highly effective system*, and uses less energy to heat a space than conventional radiators.  This is because the human body feels warm at lower air temperatures when using underfloor heating. 

The new boiler works at around 92% efficiency, saving fuel but increasing comfort and reliability.  In common with all our Grant boiler installations, our customer received a 3 year on site warranty on the boiler.

*The only type of underfloor heating to be avoided is the electric type, because electricity costs around 12p per Kwh, compared to around 4.5p for gas fired heating and 6p for oil fired (this was written in June 2009). 

Don’t be fooled by sales literature claiming electric heating is 100% efficient and green, these are half truths.  Electrical heating uses energy generated by (usually) coal or gas in the UK.  From the power station to your house meter box, around 55% of the energy in the gas or coal burnt at the power station is lost in generating and transmission losses. 

So before even fitting underfloor heating, electricity is only 45% efficient.   And that generating efficiency partially accounts for the frightening price.  So a sales person could say electric heating is 100% efficient, but it would be a half truth.  If they said it was cheaper than gas or oil fired heating, it would be a lie.  The only electric heating that is efficient in comparison is using a heat pump, but that is addressed elsewhere on this web site.

This unit replaced an old Ideal Standard cast iron boiler in a storage room.  The Ideal Standard WM series unit was a bit long in the tooth, and was probably only 65% efficient.

We specified a 12Kw Worcester Bosch Ri replacement, which can achieve an efficiency of over 90% when used on a like – for – like basis.

New boiler (insulation to pipework not applied when photo taken)

The Worcester was mounted in a similar position to the old unit, but first we had to brick up the large flue aperture remaining from the previous boiler. 

The next door neighbour had recently had their boiler replaced by another contractor, who had elected use cement instead of bricks!   Hope it was a very cheap job!

The scene outside

A new Honeywell radio thermostat, and a new two channel timer was installed.

New Honeywell Line-of-text heating and hot water programmer

As usual, the system was comprehensively power flushed and our customer benefits from a reasonably priced, quality installation, warranted by Worcester Bosch until April 2014.