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.

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.

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)

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.

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.

Crystal Palace, our secret location

A TCWS Charger and mainsboost system was fitted, connected to an existing Gledhill Boilermate III heat store.

Charger & Mainsboost installed in garage

Now all the showers work on all floors. 

Charger/Mainsboost is a specialised water boosting product which utilises the ruling that water can be pumped from the mains at up to 12 litres per minute.  The water authorities are very particular at how this can be done, and in order to get approvals the manufacturer took around two years perfecting the design to prevent any possibility of backflow etc.  Once installed the Charger/Mainsboost can support flow rates of in excess of 40 litres per minute at pressures of up to 4bar…..irrespective of the quality of the supply.

Hot Water & Central Heating are your local and experienced specialists.

The secret to successful showering is in the garage

This has resulted in a pressure just above 1bar on the lower ground floor;  this house is on 4 stories and there are bathrooms on the 2nd and 3rd floors.  The result was that the bath took ages to fill, the shower on the 3rd floor could not be used, and the shower on the 2nd floor was poor.

Protests to Thames Water from most of the residents in the immediate area did not result in satisfaction, because they were supplying over the statutory minimum pressure to the bottom floor of the property.

Hot water in these properties is supplied through a Gledhill Systemate III heatstore.

Hot Water & Central Heating were asked to provide a solution for the problem, retaining the existing boiler and heatstore.

We fitted a TCWS Charger and Mainsboost system in the lower floor garage.  This innovative patented unit consists of a pumpset and an accumulator.  The pumpset uses less than 12 litres per minute and incorporates anti backflow protection, enabling it to be connected directly to the water main.

TCWS Charger and Mainsboost in garage

It is very quiet in operation, and charges a large accumulator on a ‘trickle’ basis to replicate the performance of an accumulator on a 3bar main.

The Pump incorporates programming to manage the duty cycle and the maximum/minimum pressure.  Once commissioned, the system needs no further adjustment and will continue to run in a power cut.  If the pumpset fails, an automated bypass allows the mains to still enter the property without user intervention.

If you have a water supply problem, and are in our area (see our main ‘areas covered’ button at the top of the page) we can advise you.

Following commissioning, our customer was very happy with the results, which now means that all bathrooms are fully back in operation.  We have already been asked to provide two other nearby households with quotations for similar systems.

Stop Press:  Following the success of this installation, Hot Water & Central Heating have received an order to install an identical system to the house next door in May 2009.

In common with many houses in this area, an old gravity fed hot and cold water system using loft tanks was employed. 

Our customer wished to gradually update his house to new mains pressure fed bathrooms, using European high pressure taps, and wisely didn’t fancy the prospect of shower pumps.

He also wanted to make use of the loft space currently occupied by the large water tanks, and remove the old copper hot water storage cylinder on the 1st floor to make room for another shower.

Our brief was to design the plant to deliver his requirements, all within a cellar a little under 6 feet tall.

In the cellar we found a venerable Kidd Boiler, dating from 1990, so this was retained as it probably has a good few years of life left in it.   Launched in 1982, it was an early condensing high efficiency design that remarkably few ‘heating engineers’ have heard of to this day, even though it was probably the first commercial British condensing boiler.  Still made today, we still fit them!

Kidd Boiler Model 2 Gas (now available in white!)

I commonly hear ‘how reliable’ someone’s old Potterton has been……….  if they had fitted a Kidd instead 20 years ago it would have been just as reliable but burnt just over half the fuel in the intervening 20 years.  Notables including the Highgrove Estate and Peter Gabriel were savvy enough to understand the importance of not wasting fuel back then, but that’s another story….

We had to boost the water flow rate from the 20 litres a minute provided by Thames Water to in excess of 40 litres per minute.  We did this with a stored water pressure vessel.

We then needed a hot water storage system that could fit below the low ceiling, but have a fast recovery time in the event of concerted use.  We looked into a heatstore, but the costs of having a special unit fabricated to meet the space restrictions were very high.  Also the Kidd Boiler does not modulate, so ideally we would need a heatstore with a 46Kw plate heat exchanger to enable the boiler to discharge its power in a long burn, rather than a protracted series of short cycles, which wastes energy needlessly.

We ended up specifying the ACV Smartline tank in tank ‘unvented’ cylinder instead.  To those of you who think of a Megaflo when unvented cylinders are mentioned, this is a World apart.

ACV cylinder cutaway

The stainless steel water cylinder containing your hot water is suspended within another steel cylinder containing the boiler heated water.  When the water is heated it is surrounded 360° by the boiler water, resulting in a very fast warm up time indeed. 

So our Kidd Boiler can discharge it’s full output of 46Kw into the ACV cylinder, resulting in a quick heat recovery period.

The ACV cylinder has another trick;  although it is an unvented cylinder, it is designed to store water at 80ºC, rather than the 60ºC usually used.  The reason we normally store hot water at 60C is that at temperatures above this, limescale is precipitated from the water and deposits scale.  The ACV inner cylinder is ribbed, and every water draw off causes a movement, this prevents scale from building up.  The electrical immersion heater is fitted to the other jacket, so never scales up.

The result is that we can store more hot water energy in an ACV cylinder than an equivalent sized alternative, and most boilers will work more efficiently when driving them. 

Water Boosting Vessel and ACV Smartline hot water unvented cylinder

The equipment was all mounted well below drainage level, so a Drainmaster high temperature compatible pumpset was fitted.  The Kidd Boiler used to disharge its condense into a plastic 2 gallon drum (nobody manufactured condensate pumps in the 80s and 90s, so this was a common bodge), but now it can use the Drainmaster, along with a soon to be fitted sink, washing machine and of course the emergency discharge from the unvented system.  The Drainmaster is a pump in a vented sump, and is hot water rated for these types of application.

The outside Kidd flue had been damaged by builders, so we commissioned a new hand welded item from Kidd Boilers  (Mr Kidd, as usual, had the original installation drawings on file)

Finally, the latest Honeywell programmable room heating controller (CM927) was added to the installation to bring it up to date.

Honeywell Programmable room thermostst

We think the showers are now almost too painful to get under……..  but some of our customers like them like that!

When finished, the building will incorporate a modern kitchen, and comprehensively remodelled interiors.

We have assisted our customer in the selection of the heating system, but they have also contributed much to the specification, including the innovative Jaga Strada ‘low H20′ high efficiency radiators.

HWCH will be fitting a large underfloor heating grid on the ground floor, a 46Kw Viessmann 200 series light commercial boiler, accumulator boosted DualStream hot and cold water system, all controlled by the Honeywell Hometronic radiator and underfloor control system.

The industrial gas meter has been moved as part of the works, and our commercial gas engineer will be installing a new underground service to the house and swimming pool boilers.

Work is expected to finish in early 2009, but for now,here are some photographs;

Viessmann 46Kw boiler in utility room

Part of the underfloor heating grid just installed

Cylinder cupboard 35mm pipework under test

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.