The venerable Kidd Very High Efficiency (VHE) boiler is one of my favourites.  Designed for Archie Kidd’s personal use in 1959, and then productionised in 1982, it has been the forerunner in condensing high efficiency technology in the UK for 30 years.  Forget all the stories you hear about the Vaillant this, or the Worcester that, or the Baxi Bla Bla, the Kidd VHE was the first and last, the design is still current today, and 98% unchanged.

OK, so you’ve got a Potterton Kingfisher and it is still going after 25yrs?  Not a big deal.  The Kidd was available 5 yrs earlier and would have delivered 90% efficiency, instead of the 60% or so managed by the Potterton.  Think of all that fuel you’ve wasted!

That’s why Highgrove has a Kidd, along with other famous users, for example, music luminaires such as Sir Tim Rice, Peter Gabriel, Bjorn Ulvaeus.  And some less notable people, such as me.

Grade II listed farmhouse - beautiful!

Here we are in a Kent farmhouse, near Sittingbourne, and they have a 1983 Kidd oil boiler.  Now 28 years old, it is showing some signs of wear.  Mr Kidd has offered to refurbish it (yes, really) but the owners are remodelling the area once used as the boiler room, and there is insufficient space for the Kidd unit.

They will be sorry to see it go, but have been delighted with the economy and longevity it delivered.  And being solely mild steel, it is completely recyclable.

End of the road after 28 years of preventing energy wastage.

Connected to a very old (we reckon 1930s) one pipe heating system, we specified a new Worcester-Bosch oil Camray Greenstar utility.  This occupies only around a third of the space of the Kidd unit, but delivers a similar efficiency.

It is not going to last 28 years, but does come with a 6 year warranty due to a promotion Bosch are offering key installers at the moment (installation was Aug 2011).

Another neat job.

The one pipe system is perfectly compatible with a Worcester oil boiler, but it is difficult to remove debris in the pipework, due to the ‘Powerflushing’ systems not being effective.  Basically, with a one pipe system, the connection of one of our large Norstrom machines justs sends the high velocity water round a wide bore loop, with little effect*.  Instead, we fit a dirt separation device, in this case, a SpiroTECH Magnabooster2.  This can be emptied periodically by the homeowner.

*Some Powerflush machine manufacturers claim their machines can clean a one pipe system.  Simply not true.

The new boiler was tucked in the corner of the new utility area.  Some of the old 3″ pipework was rerouted and simplified to provide extra headroom in the new kitchen.

Finally, we fitted an additional cast iron school radiator in the lounge, and some modern programmable temperature controls by Honeywell.

New space efficient installation completed

OK. so we’ve covered a Worcester -Bosch gas boiler using an existing chimney, so here’s an oil boiler version.  Sticking with Worcester-Bosch, this one is a Camray Greenstar 18/25 Utility model.

We’re in a remote area south of Dorking, Surrey, accessed via a long farm track.

Farmhouse exterior

The property had a Trianco oiler, made around 16 years ago, with a leaking heat exchanger.  This is the end of the road for an oil boiler, because the heat exchanger is the whole metal frame of the boiler.

Facing the wrong way

Trianco have always been a budget boiler manufacturer, and have, as a company, seemingly lurched from one collapse to another, most recently last year, when their remnants were bought by an Essex metalworking company.  The other cheapy manufacturer, Perrymatics, failed many years ago.  But there are still lots of these products out there, because they sold so well.

The Trianco was connected to an old metal flue liner, incompatible with modern high efficiency condensing boilers.  For some perverse reason, the boiler had been mounted in an external boiler house sideways, rendering maintenance very difficult and compromising minimum manufacturer clearances.  This lack of access probably resulted in the boiler not being cleaned internally and the premature failure of the heat exchanger.

Original oil liner terminal on right, gravity is all that holds the tile cap on!

From measurements, we found that we could site the new Worcester -Bosch Camray unit facing forwards, enabling easy maintenance and compliance with manufacturer stipulations.

The Worcester-Bosch Flexiflue employed is near identical to the one used in the gas boilers, except that it is used for exhaust gas only – it does not provide an air inlet for the burner, this has to be arranged in the boiler room.

Instant access!

We used our preferred means of access to the chimney in the form of a 7.5ton elevating platform truck.  This is quicker than scaffolding and less likely to cause damage to the surrounding roof areas.

New liner on the way up

New flue termination completed

The new boiler was complemented by revised heating controls, including a Honeywell CM907 programmable room thermostat with Optimisation.

Finished installation

We’re in Purley, Surrey.

house in Purley

Our customer has an old atmospheric Potterton Kingfisher II 100,000 Btu in the basement, connected to the internal chimney system.

Old Potterton Kingisher

We could have resited the new boiler on the external wall but the flue outlet would have detracted from the external aesthetics of the house, so instead we discussed the option of connecting the new boiler to the old chimney system.  This is always the more expensive option, because the new liner system has to be installed from the rooftop and comprises a large number of parts.  However, in this instance, our customer wanted an ‘invisible’ installation so we specified the Worcester Bosch Flexiflue system.

Using a new, high efficiency condensing floor mounted boiler from Bosch, the FS30CDi (FS being floor standing), the Flexiflue system necessitating constructing a closure space under the old hearth termination.  This was built using blockwork.

New blockwork construction for Flexiflue termination

The chimney section above the roofline was found to be unstable, so the upper part had to be partially demolished and rebuilt.  This is not unusual as the heat and the tars tend to crack the mortar, allowing water ingress and subsequent frost damage over the years.

Old chimney needed some TLC.......

The new boiler extracts the exhaust fumes through a 60mm diameter flexible plastic tube all the way to the chimney top;  condensed water from the saturated vapours runs down the liner into the boiler and then to the drain.  The remaining ‘annulus’ of the chimney (in other words, the space remaining between the brickwork and the 60mm liner tube) is used to provide the air for combustion from the roof.  For this reason, the chimney has to be in reasonable condition, making the installation classed as ‘room sealed’, in other words, much safer than before.

new terminal almost completed

We are regularly asked whether the existing flue liner system in a chimney can be reused on a modern high efficiency boiler.  With a few possible exceptions for light commercial boiler applications, where a high efficiency boiler with a bespoke flue system may have been installed previously,, the answer is always negative.  This is because conventional boiler flues connected to a chimney liner require the liner to withstand high temperatures (up to 260C), and be made of a material not necessarily watertight or corrosion proof.  In contrast, a modern high efficiency boiler may only need a flue liner capable of withstanding typically 80C, but has to have resistance to water and acid.  The two solutions are mutually exclusive.

New Worcester FS30CDi boiler (before new blockwork and flue installed)

Unfortunately, my poor understanding of all matters iPhone has resulted in the loss of a large number of pictures for our installation gallery, but we still have a selection from this job.

NB: Other flue lining solutions we offer are available with Viessmann boilers, both domestic and light commercial.

Our customer has recently bought a property in the Esher area.

Built around 25 years ago, it was heated by two separate Johnson & Starley warm air heaters, one per floor.  For hot water, a 295 litre direct gas fired AO Smith cylinder was installed upstairs.  There was also a large gas hob and a gas fire.

Johnson & Starley Warm Air and AO Smith Water Heater

When we totalled up the load for all these appliances, it was around 92kW.  This would have been fine, apart for two key problems.  The first is that the property had a standard domestic metered supply, which has a maximum design load of around 64kW.  The second problem was tha the gas meter was located a considerable distance away from all the appliances, in a detached garage, and the pipe from the meter into the house was just 22mm in diameter.

This meant that all the appliances were being supplied with a dangerously low pressure.  All the more remarkable was that the units had been serviced each year, by a CORGI/Gas Safe firm.  The same firm that had installed them 25yrs ago, it transpired.

Our customer was faced with either upgrading the gas supply to a light commercial meter, or making changes in the property to reduce the load and keeping the domestic supply.  Unfortunately, the light commercial meter option involved the excavation of a long drive and a huge bill from the gas supplier.

Having conducted some heat calculations for the property, we realised we could replace the heating and hot water system with a modern high efficiency solution and stay within the maximum load of the existing metered supply.

We specified new Lennox G61MPVT condensing warm air units, to replace the old Johnson & Starley equipment.  The G61MPVT is a US made unit that is simply light years ahead of any other warm air heater in the UK.  Delivering an efficiency in excess of 94%, these gas fired warm air heaters are quiet but have powerful fans, designed for minimal electrical consumption.  The units can work vertically or horizontally, and can direct their airflow upwards or downwards, simply by inverting the heater.

New upstairs installation, Lennox to the left, Trion filter above

We also specified Trion air purification units for each heater. Trion high efficiency electronic air cleaners will collect particles down to .01 microns in size and that includes those hazardous, invisible particles, such as tobacco smoke, atmospheric dust and bacteria and even some viruses. So efficient is the Trion high efficiency electronic air cleaners that up to 99% of airborne impurities that enter the unit are removed.

Dave our ductwork specialist working on a Trion air purifier

We engage a specialist ductwork fabrication and installation company to carry out all our modifications on site, for a professional finish.  Many of our competitors use flexible tubes and duct tape, but this is bodging in our view.

Ductwork prepared for new Lennox heater

For the hot water, we had a bespoke Gledhill Solar ready cylinder built, with a storage capacity of 300 litres.  This has a dedicated gas condensing boiler dedicated to heat it, in this case we specified a Vaillant ecoTEC+ 615 system boiler, which was mounted on a support built by us between the prestressed roof timbers.

New Viallant ecoTEC+ system boiler in loft

A much larger gas supply pipe was needed from the meter to the warm air heaters and the Vaillant gas boiler.  It would not have been practical to run a large 35mm outside diameter pipe through the length of the property, so we suggested the driveway was excavated for a modest length, and the old flueway from the downstairs warm air unit used as a duct to get the pipework into the loft.

New pipe from meter to house

A rigid stainless steel gas pipe called TracPipe was used, which allowed us to run internally and externally with no joints, apart from adjacent to the appliances.  This is inherently safer, and gives less resistance to the flow of gas because there no elbows or restrictive connections.

Driveway reinstated!

Our new gas supply to warm units running inside garage

Our new supply pipe (yellow top right) to house

The entire task took 8 days for 3 men, the job was completed in March 2011.  Our customer was wonderful to work with, tea and coffee was on tap together with some rather nice choccy biscuits.

Downstairs boiler intake/exhaust terminal

The heat distribution is better with the Lennox than the old J&S units, because the fans are more powerful.

Here we have a large private residence in an exclusive area of Hove, near Brighton.

Part of the property and one of our vans!

Our client had just purchased the property, and engaged us following finding this blog on our web site.

There were two main tasks;  firstly, one of the two boilers for the property had failed and was beyond economical repair.

The second problem was the water supply.  The road is on the top of a hill overlooking the coast and the water flow rate was very poor, in the region of just 8 litres per minute.  The static pressure was also poor, varying between 1.0-1.5 bar.  Our customer did not want to use the shower puumps, finding them too noisy, he wanted a modern unvented system.

We proposed fitting a new Worcester Bosch CDI conventional condensing boiler, to restore the heating to the house.

New Worcester Bosch 30CDi conventional condensing boiler

In order to transform the cold and hot water, we fitted a Trentclyde Charger and Mainsboost system, which was located in the garage.  The garage floor sloped, so we construucted a plywood base for the two 450 litre tandem accumulators.

New accumulators and Charger in garage

For the hot water provision, a Vaillant uniSTOR 310 litre unvented cylinder was installed in the loft space, having removed an old horizontal hot water cylinder and an assortment of cold water tanks.

The system can now deliver mains pressure wholesome water to all outlets, at a static pressure in excess of 3bar. Flow rates of 50 litres/min can easily be supplied, the accumulator banks being sited in the garage, have taken no additional space in the house.

Like all our systems, this was specified, designed and installed by ourselves.  The Worcester-Bosch boiler is warranted for 5 years.  The installation was completed in late February 2011.

Our customer in Warlingham, Surrey, UK was having a substantial extension to the side and rear of the property.

Part of the front elevation

We were asked to specify a replacement for the existing Lennox warm air system, using a mixture of radiators and underfloor heating.

Numerous bathrooms in the house and a new annexe were to be converted to mains pressure hot and cold water systems.

We designed a four zone heating system, for maximum energy efficiency.  An unvented hot water system augmented by a TWS water boosting accumulator supplied the bathrooms.  A Worcester 30CDi boiler provided the engine room function.

Part of the garage plant

At the customer’s request, all the plant was to be located in the new garage.

Pipework detail

Worcester Bosch CDi boiler

Underfloor heating in new kitchen/dining areas

Lastly, we have a moody picture of the Vaillant 310 litre unvented and the accumulator.  I take some terrible photos with my iPhone and this is one of them.

Bit dark here

Our customer was very pleased with the installation, which they said performs just like we promised, it was fully completed in January 2011.

Here we are near Tunbridge Wells.

Near Tunbridge Wells UK

Our customer had an old wall mounted Boulter Camray oil boiler on the rear of his house.  The unit was beyond redemption, having had a small internal fire.

Old boiler bites the dust

He quite fancied moving the boiler further away from the house, so we looked into moving it down the garden.  Our customer was a builder, so he created a neat pipe trench and raised boiler plinth to our specifications.  The property has a river running nearby, which has been known to flood, so the raised platform will protect his investment!

Our pipe trench

We suggested a Worcester-Bosch Camray external condensing high efficiency oil boiler would do the trick.

Worcester-Bosch Camray external

The new boiler was connected to the house using barrier plastic pipe, which has low flow resistance and good resistance to frost.  It was insulated with Armaflex external grade insulation.  External armoured cable was laid in the duct and an RCD fitted to enable safer maintenance and accordance with BS 7671.

In common with all our Worcester-Bosch oil installations, the boiler is covered for 5 years on a full parts and labour basis by the manufacturer.

We’d like to extend our thanks to our customer, Ernie, who made a fantastic job of all the preparatory building work, in between replacing his lounge floor!  Our team was awarded with some rather nice wine at the end, too!

Our client lives in our base town of Edenbridge, Kent, UK.

Edenbridge house

Neat kitchen integration

This is another installation example of a situation where it is requested that we fit a new high efficiency boiler to an old chimney stack.

We are in the town of Sevenoaks, Kent (UK) where there is a 35 year old floor standing Potterton boiler in the breakfast room, using a flue passing inside a brick chimney.

Old Potterton boiler - casing removed

We specified a Viessmann Compact WB1B 26Kw unit, with a sealed system chimney liner.  This allowed us to install a room-sealed boiler using the stack for exhaust and fresh air inlet.

Getting ready to re-line the chimney

Old boiler flue liner removed

New Viessmann roof terminal being installed, new mortar rendering

We removed the old boiler, rationalised the pipework.  The customer then had the chimney swept, we installed a scaffold tower outside and fitted the Viessmann flue lining and termination kit.

Halfway through the job - old flue hole to be bricked up

Job done, a 30% improvement in boiler efficiency – and the house was unchanged.  Every other ‘gas specialist’ the customer had round said it couldn’t be done.  They should get out more!

Finished - only brown paint required

Refurbish a 20 year old condensing boiler?  If you have to read this twice, then you probably haven’t got a Kidd VHE.

Somewhere near Canterbury

Our subject of this blog is a 1990 Kidd Oil Model 1 unit in Canterbury, which had been ’serviced’ in recent years by a contractor who was not familiar with the product, or condensers generally.

The condense drains were all completely blocked and full of shale deposits, causing damage to the upper part of the boiler and casing.  This had probably gone unchecked for a number of years.  As a result, the projected 30 yr lifspan had been cruelly truncated.

Economiser was suffering from not being cleaned

We advised the customer that for the price of a new Grant or Worcester unit – which are well made mass market units – we could refurbish his Kidd boiler.  Having seen the build quality of this unit, and having had 20 years reliable service from it, he opted for the rebuild.

A naked Model 1 and a clothed Tim

A new ‘economiser’ was fabricated by Kidd boilers, together with a new flue.  Although the old boiler was 20 yrs old, the new upper section fitted perfectly, because the design is fundamentally unchanged from its inception in 1981.   To finish the job off, a new Sterling Kidd 40 series oil burner was fitted.

Old flue with blocked condense drain tube

New flue incorporating bends to slow down condensate to prevent splashing in the heat exchanger

We Powerflushed the radiator system, removed some copper based condensate tubing (still in parfect condition after 20 years), and fitted some modern Honeywell programmable thermostat controls in the house.

Our customer was thus equipped with a Kidd boiler virtually the same as a new one, to see him through the next few decades with ‘A’ rated efficiency.

As I often tell our customers, condensing boilers aren’t new technology, that is a myth created by politicians to try to take the credit for energy savings.