Inside a Vaillant ecoTEC + 831

We advised them to fit a new Vaillant ecoTEC+ 831 combination boiler, because it is a well built unit and reliable for a lettings customer.  All our Vaillant installations benefit from a 5 Year manufacturer parts and labour warranty.  We have fitted a few hundred of the Vaillant ecoTEC+ combi over the past five years and found it to be a reliable product.

The system was fully Powerflushed, and the new boiler fitted.  A Vaillant ‘Plume Management Kit’ was used to divert the exhaust steam to a high level outside.

Vaillant plume management - and a faulty gutter downpipe!

The old hob was replaced with a new Bosch unit, featuring an FSD.  Flame Supervision Devices are now mandatory on hobs fitted in rented properties.

New Bosch gas hob

We supplied a new Landlord Safety Certificate for the property.

Old boiler location was to the right hand side of the cellar steps

The hot water cylinder was located above the cellar on a raised floor, which would have been the first landing of the stairs in the Victorian property’s original layout.

Old hot water cylinder location, floor to be lowered to make new bathroom

Sited in Caterham, Surrey, it would be fair to say that the heating system had been bodged up by the previous owner, along with the electrical work.  Various leaking parts had seen the attention of a silicon mastic gun, including radiator valves.

Our customer rather liked the idea of fitting a new bathroom in the area previously occupied by the hot water cylinder, and this meant lowering the floor, which from our perspective meant;

- a combination boiler

- relocation into the cellar for all the boiler plant

The problem with locating the boiler in the cellar is getting the flue out, and dealing with the boiler expansion relief and condensate water.  There is a boiler available in the UK which has some very flexible flue arrangements which would seem ideal for this application called a Keston, but for reasons we’d rather not go into in this public forum, they are never specified by ‘Hot Water & Central Heating’.

We fitted a Vaillant ecoTEC 837 in the cellar, and used a void area to run the flue to a suitable height for a horizontal discharge.  Gas Safe Register are quite rightly insisting that flues in voids must be able to be visually inspected and suitable arrangements are in place.

New boiler and high temperature lift pump below

The condensate and high temperature emergency discharge from the boiler were handled by a new condensate lifter product specially designed to accept high temperature water, this is unique we believe.  We no longer fit the Vaillant branded condensate lifter because Vaillant UK exclude it from their extended boiler warranty.

A Mainsboost GC450 accumulator was also fitted in the cellar to boost the water flow rate and separate the water supply, as the other 5 flats in the building cause water starvation issues as they are all fed from the same rusty water main around 200 metres long.  The water main here was delivering a very high static pressure, peaks of around 7bar were measured.  A pressure reducing valve was fitted to protect the appliances and provide a uniform performance via the acumulator.

The boiler exhaust was fitted with a Vaillant plume management kit, in white to match the building, as cars often part in the vicinity of the flue outlet, and the mildly acidic condensation could cause damage to paintwork.

New Vaillant boiler flue (in white)

Let the work commence

Now theres’s nothing wrong with warm air heating, and we fit the latest US Lennox condensing units for the more discerning customers.  But in common with many properties of this era, economies had been made with the ductwork, resulting in no direct heating of the third bedroom or bathroom.

Our customer had recently bought the property, and faced the choice of many similar households wondering whether to replace the warm air based boiler for a new one or pull it all out and put in a ‘wet’ radiator system.  It wasn’t practical to extend the warm air ductwork into the unheated area, so we suggested fitting a Vaillant ecoTEC+ 837 combination boiler in the front of the garage.

Nearly finished

We managed to utilise some of the old ducts in the property to conceal the new heating pipework, and lifting flooring elsewhere, resulting in a very neatly finished installation.

New radiator in the kitchen

Pipework detail

The relocation of the heating system meant that a very large cupboard was released in the kitchen, which is never a bad thing!

Insulated pipework inside garage

Our customer was very pleased with the results;

“I just wanted to say a big thank you to Simon and Hot Water Central Heating.  We are very

pleased with the work that’s been carried out – apart from the

radiators (we didn’t have them before) you’d never know the guys had

been here.

Sadly, we’re looking forward to it getting cold so we can test it out.

Happily recommed you to anyone.”

They wished to remove a couple of shower pumps and the water tanks and install a direct fed pressurized water system.  The problem was that the water flow rate into the property was around 9-10 litres per minute.  There was also a limited space to fit the entire boiler plant into.

It's easier to plumb the accumulator in this position

We had to boost the flow rate as well as provide the new boiler plant, all within a single cupboard.  We chose to fit a wall hung Vaillant ecoTEC 937, which is a ‘hybrid’ condensing combination boiler.  Most combination boilers heat water as you use it, but this restricts the available flow rate to around 15l/m for most units.  Hybrid combination boilers store some hotter water in preparation for usage, and then mix this with the water they ‘heat on the fly’ when a tap is opened……in the case of the Vaillant 937, this delivers the equivalent of 20 litres per minute of hot water for the first 10 minutes.

As we use hot water in bursts of activity, and then the system lies dormant, the hybrid combination boiler is a versatile solution.

But of course, we can’t get 20 litres a minute of hot water out of a water main only supplying 10 litres/min – so we also specified a Trent Clyde Mainsboost accumulator.   This stores water at pressure and enables a highly boosted flow rate when required.

Commissioning checks underway

With the accumulator, flow rates including cold and hot water of 30 litres per minute are easily achievable.

The finished hot and cold water/heating solution

We added a secondary heating expansion vessel, as the unit in the Vaillant boiler is only suitable for a modest volume of radiators.

The flue aperture was made good outside, and the decking lifted to provide a neat direct condense drain into the external drainage.

External discharge shown

As is usual with our installations, our customer has an extended Vaillant boiler warranty, from 2 years to 5 years.

It was late when we finished

He had considered a solar hot water system in the loft, as he wanted to minimise his family impact on the environment;  with solar hot water it is important to maximise the hot water storage, or you quickly run out of solar heated water and have to use the boiler.

Unfortunately, the design of these properties leaves a low headroom in the loft, restricting the size of cylinder, and there is limited weight capacity for large volumes of water.

So, instead, he decided to fit the Vaillant ecoTEC+ 937 hybrid combination boiler.  The wall hung unit comprises an 837 combi with a set of hot water storage tanks built in a pod at the back.  This makes the boiler quite large and heavy (getting on for the size of a washing machine), but it delivers a superb performance of 20 litres per min for the first 200 litres of drawoff.

We fitted the new boiler on the brick gable wall and used a vertical flue system.  Five new radiators were also supplied and fitted, and we were fortunate to be able to use some existing ductwork from a warm air installation to hide most of the pipework.

New Vaillant 937 in the loft

The Vaillant 937 is a good alternative to an unvented cylinder and boiler in a medium sized house, because it takes up relatively little space.  Other similar solutions offered by Hot Water & Central Heating include the Worcester Highflow CDi range.

Period house in Warlingham, Surrey

Our client has a woodworking business and was constructing an imaginative barn type conversion for their property, with lots of oak beams in an unusual semi circular design.

Firstly, we installed a Heritage Cooker in the existing kitchen.  Fitted with brass trim and a Jade Green enamelled finish, it was also specified with body colour hotplate covers.

Heritage Cooker

This particular Heritage Cooker was a gas fired unit, most of the Heritages we fit are oil fired in very rural locations.

In common with all 3 oven Heritage units, the control panel concealed behind the upper left hand door enables the unit to be timed according to the user requirements. 

Showing hidden control panel

From cold, the Heritage is ready for cooking in as little as 25 minutes.  Try telling this to an AGA owner and they start getting very defensive.  Especially in the summer when their cooker is making the kichen intolerably hot and using completely unnecessary amounts of fuel!

An old Potterton boiler and associated hot water cylinder was removed, and a new Vaillant ecoTEC+ 937 hybrid combination boiler was installed in the extension, together with a new water main.

Vaillant 937

We have fitted lots of this model over the past 18 months.  ecoTEC937 uses a buffer store of preheated hot water, to give a performance of around 200 litres of hot in the first 10 minutes, all from a (large) wall hung boiler.  This is a boiler that is a viable alternative for a small unvented cylinder installation for water delivery, if there is only 25 litres per minute coming in the property.

Separate circuits were installed for the underfloor heating system in the extension and the main radiators in the house.

Underfloor heating and radio controls

The underfloor heating manifold (and electrical consumer unit above) will be concealed inside a larder kitchen unit later in the project.

The underfloor heating is fitted with the OJ electronics radio thermostat system, so our customer has 4 zones of independently controllable underfloor heating, plus a separately timed and programmable radiator system, giving 5 addressable zones of heating in the house.

All ready for Christmas 2008, and the floor tiler!

The old Ferroli combination boiler was past it’s best and had been built into a rather ugly wooden housing about 2 feet from the corner of the kitchen, conveniently preventing a line of shiney new kitchen units from being installed.

The siting of the old boiler had been necessary because it used the old ‘balanced flue’ type termination, which involves an outside termination to British Standards, avoiding two windows.  At it happens, the boiler flue termination was too close to the kitchen window anyway.

New boiler being installed

We fitted a new Vaillant ecoTEC Plus 831 combination boiler.  These can be fitted with a small diverter pipe outside to lead the flue gases to a higher level, leaving just the air inlet for the boiler near to the window.  Vaillant allow such installations to get as close as 75mm to an opening window, significantly increasing installation flexibility.

We were able to turn the boiler through 90 degrees from the old position (you can see the old rectangular flue aperture in the picture, denoting the old boiler position), enabling our customer to install a lovely new kitchen with wall units all along the right hand wall.

The boiler was connected to the Powerflushed pipework and radiators, which although 30 years old, were in excellent condition.

Powerflushing is perhaps amongst the most dull jobs in the World, but a clean system makes boilers last longer and more reliably.  With our 5 year manufacturer warranty, this installation will be going strong for many years.

HWCH were asked to suggest a new gas central heating system design, to replace the existing electrical heating system.

A Vaillant ecoTEC 837 fast flow combination boiler was sited in the loft; as no suitable locations existed, we constructed a frame with a fire resistant lining to support the boiler and accessories.

The boiler flue was passed through the pitched roof, all external works as usual were entrusted to our specialist roofing contractor.

The job included 10 Vogel & Noot radiators, and the new Vaillant VRC430 weather compensation system.

We are great believers in the principle of weather compensation; that is, changing the temperature of the radiators according to external weather conditions to the lowest possible. The simple benefit of such a system is that your boiler is always working in the highest efficiency band possible, so you use the minimum amout of fuel – and give off the least emissions.

A properly installed Weather Compensation system does not lower the room temperatures from optimum, so there is no trade off in comfort terms.

We just wish the manufacturers would make it easier for homeowners to understand!

The new Vaillant VRC430 is a huge improvement on their previous controller (VRC400) in this respect.

As a footnote, we have subsequently received very nice letter from our client – a copy of which is available in our office for inspection!