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.

Completed in early April 2009, this customer’s house, on the Sanderstead/Purley borders (Surrey, UK) had an aged Potterton boiler removed and changed for a new wall hung Worcester Bosch 24Ri.

Who left that van there?

The new boiler was a third of the size and weight of the old unit, but had exactly the same power output.

The old cast iron unit had been very reliable, but extremely wasteful of gas.  Old floorstanding cast iron units rarely give an efficiency of greater than 65%. 

A new high efficiency boiler will achieve around 90% efficiency.

In other words, comparing the old boiler to the new one, for every £1.00 you spend on gas, 25p is immediately lost, forever.

And of course, if you are using less gas, your household emissions will lower, and there will be considerably more gas left for everyone else.

Inside the utility room

The only losers are the people selling you the energy in the first place…….. 

Getting back to our installation picture file, the old boiler had an enormous balanced flue which we painstakingly bricked up to match the existing….. if you look closely you may be able to see.

Completed job, spot the brickwork remedial work

Our customer’s boiler is warranted through our preferential arrangement with Worcester Bosch, until April 2014.

We spent 3 days in this loft

Our customer in Purley had a boiler fitted by Hot Water & Central Heating in 2005, and was in the process of having a bathroom refitted. 

Vaillant ecoTEC installed in 2005 - as good as new

Their old gravity water system cylinder was in the way of a new shower enclosure.

Old gravity cylinder - recycling beckons

We worked alongside their bathroom installers (Visions) to swap over from a vented bathroom setup to a new unvented cylinder in the loft. 

Tim holding up the uniSTOR 260

Our customer is a retired chemical engineer, and he specified one of the first Vaillant weather compensated heating systems when we originally installed his Vaillant ecoTEC 630 boiler in 2005.

Naturally, he decided to go for a Vaillant unvented cylinder, in this case the uniSTOR 260.  He now has what Vaillant describe a ‘total system solution’.  This is where the boiler controls know the precise hot water temperature in the cylinder, and modulate the boiler output according to the scale of the task. 

In a Vaillant total system solution there is no separate timer and programmer, all the heating and hot water is controlled from a single wall mounted controller.  We had fitted a Vaillant VRC400 back in 2005, but recently this has been superceded by the new VRC430, and as this was an inexpensive upgrade, our customer chose to have the newer model fitted at the same time.

Latest Vaillant controller was installed

The uniSTOR was sited in the loft space, involving a considerable amount of pipework and subsequent lagging.

There was a surprising amount of pipework in this job

We also upgraded the water supply from the garage, to give the best possible performance at the taps.

New water pipe (insulated) in garage on its way to the loft

Connected to a suitable water supply, unvented hot and cold water systems give a performance level similar to that obtained from a shower pump without the noise and unreliability associated with the latter.

Finished job

They have to be installed by a qualified installer and the safety devices suitably installed;  in our case, we ran the emergency discharge pipe in 28mm copper in a discrete corner of the property, rather than using the nearer back of the house, which would have been unsightly.

Discharge pipe was run at side of house

There was a time when a backboiler (a gas fire with a hidden cast iron central heating boiler hidden inside the fireplace) was the height of fashion.

Unfortunately, the front fires now look dated, but more importantly, the bit at the back is usually only 60%-65% efficient in its use of your expensive gas.

Our customer in Pembury (near Tunbridge Wells, Kent) had decided it was time to invest in a new energy efficient boiler, and from the 3 quotes, he chose Hot Water & Central Heating for the task.

The boiler was to be moved from the lounge to a utility room area, in the process of being refurbished.

We suggested the Worcester Bosch 18Ri conventional boiler, which has an efficiency of over 90%, and comes with a full 5 year warranty when fitted by Hot Water & Central Heating.

The new boiler

The Worcester 18Ri has a depth of only 280mm, meaning that it will fit in a standard wall cupboard – which is handy, because our customer will be having new units on this wall.   The boiler will be completely hidden when renovations are completed.

In this case, we were fortunate to have the boiler on an outside wall, which made fitting so much simpler.

New boiler location, from the outside, showing neat flue outlet