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.

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.

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!

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

Our customer had an old Glowworm boiler which was in a position preventing a planned extension to the house.

The object of our works, on the Purley/Coulsdon borders

HWCH Ltd were recommended by another customer, and we suggested replacing the boiler with a modern Vaillant ecoTEC 630 system boiler.

The Vaillant ecoTEC+ 630 is a 30Kw boiler (102,000 BTu output) with an integral 2 speed pump, all mounted in a modern near-silent enclosure.

We give 5 year warranties on our Vaillant boilers, which, along with the recommendation, no doubt helped win us this contract.

New Vaillant boiler in utility room

The customer had originally carried his own central heating installation over 20 years ago, and a very fine job he had made of it.  In fact, it looked nothing like a typical DIY installation, we were very impressed.

We relocated the boiler from a WC to a utility room, and provided modern programmable Honeywell thermostatic controls, which enabled the house to be zoned into two areas.

Wiring up the new Honeywell zone valves

The boiler will be covered by a 5yr parts and labour warranty until 2013.  If your Vaillant boiler installer does not give you this, perhaps you should be calling us for a quote!

Our customer premises

Our client, an independent church ministry, occupy a building in the Nutfield region of Surrey, near Redhill.

Their original boiler was a Potterton Suprima, a model which enjoyed high sales between approximately 1995 and 2004.  Unfortunately, it also featured regularly on BBC’s Watchdog programme, due to some alleged design defects which result in the circuit boards needing frequent replacement.

This unit failed for a diffferent reason.  The Suprima can have a long flue run, if the optional Potterton twin pipe system is employed.  Our customer had such an installation, running from the airing cupboard mounted boiler, through a large loft space, to a vertical flue terminal on the rear side of the pitched roof.

Condensation had formed inside the flue (which a Potterton Suprima is not constructed to deal with, as it is a non condensing boiler), which had run back down the pipe inside the combustion area of the boiler, where it was trapped, and rotted the casing.  Result, a total write off. 

Having checked our Potterton archive, the flue was installed correctly by the original builder, so this appears to be another Suprima instance of an under developed and tested product being introduced to market.  Luckily, very few Suprimas were equipped with this type of twin pipe flue system, but if yours was, you may want to get it checked over before a dangerous situation develops.

We recommended that the new boiler, a Vaillant ecoTEC+ 624, was sited in the roof space.  The new boiler is a high efficiency condensing type, and needs a drain attached, which was not available in the airing cupboard.

Vaillant system boiler in loft space

The installed system of radiators used microbore plumbing, so was unable to be Powerflushed clean due to the frictional resistance of the pencil thin pipe.  Heating companies have been known to connect their powerflush machines to microbore, but it is utterly pointless, because the flow of water through the radiators is so small it does not have an agitating or cleansing effect.

To help protect the boiler from dirt and rust contamination in the old pipework, we fitted the latest ‘TwinTech’ from Adey systems, this captures ferrous material with a magnetic rod, and non ferrous detritus in a filter.  This unit, seen in purple underneath the boiler, is the new upgraded version of the old Adey ‘Magnaclean’ filter.

The flue was run through the loft space (shown temporarily supported here) to a new vertical terminal on the roof. 

Vaillant flue inside loft area

Scaffolding was needed here due to the roof having no apex but a hidden flat top, so roof ladders could not be used.

The neatest jobs are the ones you can't see

New Honeywell 907 thermostat in hall

Inside a Vaillant 6 series ecoTEC+

View with control panel down

Old boiler in kitchen

This unit had to go, as a refurbishment was imminent.  We recommended fitting a Vaillant boiler in the utility room.

New Vaillant boiler in utility room

The Vaillant 428 is a small open vented boiler which is designed especially for the UK market, where we often have a small radiator tank in the loft.

The boiler flue from a modern high efficiency unit discharges plume, a condensation laden steam effect rather like an old train.  Building Regulations and good neighbour relations mean that we have to be mindful in which direction this discharges.

We used the Vaillant ‘Variable Flue termination kit’ accessory to run the steam output all the way up the side of the house and discharge it safely and aesthetically, vertically next to the roof.

It was an awkward site next to a window and a gutter

The flue matches the rainwater goods in size and colour.

Spot the boiler flue

Finished job

Our customer wanted the old gas appliances removed for safety reasons, and also desired a mains pressure system to feed his new baths and showers, instead of the noisy and unreliable pumped system.

We recommended a DualStream accumulator fed unvented system.  The accumulator (which boosts the available water flow rate in the house) was fitted in one airing cupboard, and a 300 litre unvented cylinder was fitted in the other.

DualStream accumulator in one airing cupboard

The accumulator fed system discharges water at an enormous flow rate into the showers and baths. 

Shaun puts the finishing touches to the DualStream unvented HW cylinder

In fact, it quickly exposed a faulty plastic pipe joint fitted by another bathroom installer.  After a quick pop up the system was fully operational.

Vaillant EcoMax Pros in basement

The new system was adapted to run off a pair of existing Vaillant open vented Ecomax Pros in the basement.  One of these was not working but it was a simple arcing electrode fault. 

We rewired these units to work with the Honeywell Hometronic radiator management system, now our customer has full control of 16 different zones of heating.

HWCH specified and installed a full ground floor underfloor heating system, Vaillant 624 system boiler and a manifolded upstairs radiator system.  This allowed the radiators to be fed by seamless pipework, making leaks under the beam and block floor almost impossible.

New build property in Purley, Surrey. WC price on application.

Each floor will be independently controlled as well as each separate underfloor zone. 

Hot water will be provided by a Vaillant uniSTOR unvented cylinder.

The property will be completed in late 2008.

The old unit, a Potterton Kingfisher, was located in the rear of the main kitchen, and was going to be in the way of a planned refurbishment.

There were very few places to fit the boiler, so we eventually settled on a restricted location near the back doorway.  A Vaillant ecoTEC plus 630 High Efficiency unit was selected, as the build quality of these units is very good, and they are particulary quiet, featuring an insulated casing.

Vaillant ecoTEC plus 630 system boiler

The pipework had to run a long way through store cupboards etc and was sized at 28mm for maximum flow rate.  In the cupboard areas insulation was applied.

Our customer rather fancied some period radiators for her reception rooms, so we procured some customer made refurbished school radiators from our supplier, in a superb gunmetal finish.  Last year we fitted 28 of these units in a house in Tandridge, and our backs have only just healed.

School radiator, supplied and installed by HWCH

School radiator in the lounge

These radiators really lift a room.

Best of all they are truly recycled.  These are the ‘greenest radiators’ you can buy.

Local councils are taking them out of schools and institutions and throwing them away, replacing them with tin radiators that will be rusted and dented in a few years.  On one hand they play around with coloured recycling bins, and on the other they are destroying radiators that would still be giving good service in 100 years time.