FAQ
Some of the questions we get asked,
along with the answers.
What is a thermal store ?
If the stored water stays in the store, does that mean that the store never runs out of hot water ?
What are the guarantees on Heat Banks ?
Are there any limits on the positioning of the stores ?
Can I have hot water outlets above the store ?
How far can the cylinder be from the boiler ?
What do I need to check ?
Where is the best place to start finding out what unit to order ?
Do I need qualifications to install a Heat Bank ?
Do I need to worry about too high pressure from the mains ?
If the standard size of store will not fit, is there another option ?
Other thermal stores I have seen use coils to heat the water. Is this how a Heat Bank works ?
Do I need a new boiler ?
Can I use a Solid Fuel Boiler or Solar Panels to heat a Heat Bank ?
How can I ensure that I have hot water instantly available at hot taps ?
What are the advantages of a Heat Bank over an unvented cylinder?
Does the Heat Bank boost the mains supply ?
What are my options if my mains is not very powerful ?
How can I work out the size of cylinder I need ?
Can the plate heat exchanger scale up ?
Who can I get to install the unit ?
Can I see a unit before I buy one ?
Where can I get a new set of instructions ?
How do prices compare to your competitors ?
Where can I but a Heat Bank ? Do Merchants stock units ?
How does the system comply with the new regulations concerning overheat protection in immersion heaters and thermostatic control
of hot water ?
Are there any disadvantages or hidden costs ?
How long have Heat Banks been around ?
What happens is something goes wrong with the unit ?
Q: What is a thermal store ?
A: In its simplest terms - a storage unit for heat. Like hot water cylinders, a thermal store saves up
the energy generated by a boiler or electric heaters, allowing the householder to use this energy
quickly - to run a hot tap and a shower together, for example. Without storage, such as when
using a combination (combi) boiler, then it is only possibly to run one outlet at once.
A thermal store differs from a hot water cylinder in that the hot water delivered to taps is heated
instantaneously using the heat energy in the store. The water in the store stays in the store, and
remains completely separate from the domestic water supplies.
Q: If the stored water stays in the store, does that mean that the store never runs out of
hot water ?
A: No. The entire reason for hot water storage is to store heat energy, not the actual water - that is
what cold storage tanks are for. A Heat Bank will run out of heat energy and go cold in the same
way that a normal hot water cylinder runs out of hot water. Heat Banks should be sized as any
standard cylinder is.
Q: What are the guarantees on Heat Banks ?
A: 1 year on site back-up (call-outs resulting from installer or user error will be charged).
2 years on components (not labour).
20 years on the store itself (provided inhibitor is refreshed every 5 years. Not including site
damage).
Q: Are there any limits on the positioning of the stores ?
A: No. Stores can go anywhere in the property you can get the pipework to. Unlike other hot water
systems they need no discharge pipe - An unvented cylinder will require a discharge to outside,
and a standard cold tank / hot water cylinder system needs an overflow from the cold tank to
outside. Without an external discharge, positioning and installation of the store becomes much
simpler.
All we would say is that if the unit is to be located in a cold loft or cellar, that all pipework is
lagged, and the store preferably boxed in to cut-down heat loss, as you would with any hot water
system.
Q: Can I have hot water outlets above the store ?
A: Yes. As both your hot and cold water is supplied at full mains pressure, it is usually possible to
supply outlets far above the store. This depends on you mains pressure - a pressure of 1 bar can
lift water 10 metres, and likewise a pressure of 5 bar can lift water 50 metres.
Q: How far can the cylinder be from the boiler ?
A: If there is a considerable distance (>20m), then it may be wise to use larger pipe sizes to
accommodate, or to specify a higher head primary (boiler) pump.
Q: What do I need to check ?
A: The only item that needs checking is the suitability of your mains water supply to provide both hot
and cold services. Without cold storage, the mains must be capable of supplying simultaneously.
Check mains water pressure, which should be generally above 2 bar for high performance.
However, pressure alone is not enough, as the mains supply pipework needs to be large enough
to carry the required water. The best way to test the effectiveness of the mains is to open all
existing cold taps that are running off the mains to determine if there is enough water coming into
the property. More below...
Q: Where is the best place to start finding out what unit to order ?
A: Download our Panex program. This provides all standard options, but will also give you extensive
help, and will generate such useful documents as wiring diagrams, and installation instructions.
Once you have settles on a design (or two..) simply tell us the code (provided) and we can easily
quote or discuss.
Q: Do I need qualifications to install a Heat Bank ?
A: No. You simply need to be competent enough to perform basic plumbing and wiring. No specialist
unvented qualification are required.
Q: Do I need to worry about too high pressure from the mains ?
A: Not usually as the store can run at up to 6 bar continuous, 9 bar peak. You should however check
that all your fittings (showers, washing machine hoses etc.) are suitable for your mains pressure.
If you are worried then fit a pressure reducing valve set to 3.5 bar.
Q: If the standard size of store will not fit, is there another option ?
A: Yes. We can make stores to suit (within reason). We have four different unit diameters allowing
the same volume of storage in either a tall thin unit, or a short fat unit. We are also launching a
range of rectangular stores (as opposed to circular) that make more efficient use of space.
Finally, it is possible to supply a horizontal store - one that lays on its side - that can be useful
when there is very little head room. The standard size is however the cheapest.
Q: Other thermal stores I have seen use coils to heat the water.
Is this how a Heat Bank works ?
A: No. Coil type thermal stores use metal (typically copper) coiled tube(s) within the store, through
which the domestic water flows and is heated. A Heat Bank however, circulates the water in the
store (using a pump) from the top, through a plate heat exchanger, and back to the bottom of the
store. The heat exchanger transfers the heat to the domestic water that also flows through the
heat exchanger, while keeping the water separated.
We at DPS used to manufacture coil type stores (many years back) however they were always
more susceptible to limescale build up within the coils. Also, the temperature of water produced
dropped gradually from the start temperature, rather than holding steady. The use of the plate
heat exchanger overcomes these, and also boosts the maximum output considerably, with lower
pressure losses.
Q: Do I need a new boiler ?
A: Up to you. The standard options allow for all types of domestic boiler. A Heat Banks can even be
easily connected to a combination boiler to improve performance without replacing the boiler. If
you have any queries regarding boilers, it is worth checking the size of the existing boiler (if there
is one). If it is a new property or there is an extension or increased water loading (more
bedrooms) then you may need a larger boiler. As it is not good to vastly oversize a new boiler,
some reasonably accurate idea of the heating and hot water load (pattern of use) should be
obtained. We provide free software tools on this site to assist in doing calculations Calculator .This is not a service we offer as it is time consuming and requires a knowledge of the
site, but most installers, or architects should also know a thing about it.
Q: Can I use a Solid Fuel Boiler or Solar Panels to heat a Heat Bank ?
A: Yes. We have options covering both. In fact, we have supplied stores that will connect to a gas
boiler, solar panels, solid fuel stove, and geo-thermal heat source, all at the same time.
Protection is included against overheating the unit (always a worry with an uncontrolled heat
source) by the means of a dedicated hot water outlet (typically taken to a drain) that will relieve
hot water when the store approaches overheat, and thereby prevent the temperature from further
increasing. All the controls for this are factory fitted. Heat Banks are vented, so the restrictions
on connecting to a pressurised storage cylinder do not apply.
Q: How can I ensure that I have hot water instantly available at hot taps ?
A: Although the Heat Bank will generate hot water instantaneously, you may still get dead-legs in
pipework - that is a length of supply pipe between the store and the tap that goes cold over time.
The only way to overcome this (insulating pipes helps) is by plumbing in a secondary return
circuit. In such a setup, the hot water supplies are in a loop around the property, returning to the
store. A small pump can be used to keep hot water circulating around the loop keeping pipework
hot. This is an factory-fitted option.
Q: What are the advantages of a Heat Bank over an unvented cylinder?
A: There are many important benefits, not least no discharge pipe, no trained installers and no
annual maintenance - all required on unvented systems - as well as simply more water. Click
here for further information...
Q: Does the Heat Bank boost the mains supply ?
A: No. It simply heats what is already provided by the mains water pipework. This is limited by the
water pressure in your area, as well as the pipe size into the property. Both are important and
should be checked.
Q: What are my options if my mains is not very powerful ?
A: First thing is carefully check all valves, stopcocks on the supply are open (a long shot).
It is always worth contacting your water supplier to see if they can up the pressure into the
property. Sometimes, nearly always in flats, there are pressure limiting valves, that can be
increased in setting.
Maybe ask a plumber you know if he can see anything obvious - never go to an unknown (not IOP
registered for example) person asking to spot problems in your house - they may magically
appear.
Failing these, it may be necessary to increase the pipe size of the mains coming into and within
the property. Sometimes the weak point is a short link of pipework where the supply enters the
house, sometimes the entire length of pipework under a driveway will need renewing in a larger
size. If embarking on such a venture as digging up your drive - always talk things over closely
with the water suppliers as they legally only have to provide 1 bar pressure, and 9 litres per
minute (some are more co-operative than others)!
If renewing the mains supply is not an option, then there are only two options left. The first is to
stick to a traditional cold tank fed system, using pumps if needed to boost pressures.
However, if cold tanks in the loft are not an option either, then a pump set is required. This is
simply a cold storage tank at lower level, in the garage for example, with pumps to boost the
pressure into the house. Once the pump set is operating the property can go ahead with a high
pressure and high flow rate cold water supply. Typically two pumps are used in unison - to reduce
ware and provide temporary backup if one fails - as the cold tank is lower than outlets, a pump
failure will result in a complete failure of water supply, so automatic backup is advised. More on
pump sets.
Q: How can I work out the size of cylinder I need ?
A: There are two Flash Tools on this site which will enable you to perform in-depth calculations. As
a rule of thumb the following table may help, but values may vary upon general usage levels. You
can of course always contact us for advice.
No of occupants
Size of store [litres]
Electric
Indirect (Boiler)
1
130
130
2
180
150
3
210
180
4
210-250
180
5
210-300
210
6
250-350
250
Q: Can the plate heat exchanger scale up ?
A: Generally no. We are often asked by service engineers experienced with combi-boilers about this
happening, as they also use a plate heat exchanger to heat water, which can scale up. The main
difference between a thermal store and a combi-boiler is the output of the heat exchanger typically 3 times larger on a Heat Bank. The much higher flow rates generated through the Heat
Bank heat exchanger helps to clean it and prevent scale from depositing. It is very rare for
performance to be adversely affected even in hard water areas.
However, in hard water areas, we advise choosing the option to factory fit an electronic water
conditioner on the Heat Bank. This provides permanent and complete protection against limescale
deposits with the heat exchanger. It also protects the rest of the property. More information...
Q: Who can I get to install the unit ?
A: If you do not fancy the job yourself, and do not know a plumber who has been recommended by
word of mouth, then use the Institute of Plumbing web site to find the nearest registered
plumber.
Do not take on the installation yourself if you are not electrically and mechanically competent.
ONLY GAS REGISTERED PERSONNEL CAN SERVICE, REMOVE OR INSTALL GAS BOILERS.
Q: Can I see a unit before I buy one ?
A: Our factory in Epsom, Surrey is open 9 to 5 weekdays for anyone to come and see the
systems. We also provide free training at the factory for any installers concerned in mains
pressure hot water systems, of all types - we also sell and provide technical backup for ALL types
of hot water system.
Q: Where can I get a new set of instructions ?
A: We keep all documents, including installation instructions on file. Many Heat Banks instructions
are on this site, or can be generated by our Panex program. Alternatively, we can upload a PDF
containing your instructions to our web site for you (or maybe your tenants) to download, or view
online, when you need. Of course, hard copies may always be sent by post.
Q: How do prices compare to your competitors ?
A: Very well indeed. Our basic range, while still beating the performance of any other system, also
compares very favorably to the well known makes on the market. Usually, however, we are asked
for system units - rather than a basic unit these also have other controls fitted that would
normally be fitted by an installer (e.g. central heating controls). All of our major (high volume)
customers take system units, simply because the factory based assembly makes for quicker (and
more reliable) assembly and installation and hence lower overall costs and problems on site.
Q: Where can I but a Heat Bank ? Do Merchants stock units ?
A: We sell direct, holding a stock of standard sizes. Special sizes can take up to 5 weeks. Limited
companies can set up accounts, or else we can take payment by cheque or credit card. On custom
units there is a minimum 50% payment with order. Units are delivered either by our own carrier
(in the SE) or by outside carrier for longer distances. Units can always be collected if desired.
Q: Do you have a local representative who can look at my system ?
A: We generally only go on site if something goes wrong with our equipment. We do not have a
network or sales or technical reps that can provide sales or enquiry help for private customers.
We do, however, have a very experience staff who can take on most enquiries with the basic info
provided, preferably by email. If we require more info we can always phone you.
Where there is volume potential, we have the South covered, and are always willing to attend site
meetings. Further afield, we are on the look out for decent technical sales reps (commission only).
Q: How does the system comply with the new regulations concerning overheat protection
in immersion heaters and thermostatic control of hot water ?
A: Our immersion heater have both overheat and dry-fire protection, and we fit a thermostatic
blending valve to limit hot water temperatures as standard. If units are to go to care homes
requiring special types of temperature control valves, these are available.
Q: Are there any disadvantages or hidden costs ?
A: No. The units are fully pre-fabricated and tested as shown in the specifications, and are not
supplied in kit form. The use of our system is rapidly growing in private, trade, new-build and local
authority circles as a result of our design and backup.
Q: How long have Heat Banks been around ?
A: Some 10 years plus now. Most of our contracts are within the trade - local authority or new build and we generally rely on word of mouth and consultants for our main business. The earliest big
contracts we had were with London local authorities, with certain major new build companies
following, Laing Homes being the first. There are thousands of our units in London, with business
as far as Scotland.
We have no substantial news paper, or trade press advertising, other than in the Institute of
Plumbing magazine, where we often do technical editorials on various subjects. We have always
sold to the public, providing customised 1 off specials when needed - see custom unit page however it is only since the growth of the internet and our web site that we have started to
become talked about in domestic circles.
Q: What happens is something goes wrong with the unit ?
A: We provide 1 year on site backup against failures of our equipment. Our site cover is within
working hours. We do not provide weekend or evening cover - this is down to your installer.
Units have been designed to be simple in regards to wiring (no specialist circuitry) and servicing.
Full backup of instructions from our web site. All standard components are available from
plumbing merchants (although we provide 2 years cover on these) .
Please send any technical questions to admin@heatweb.com
Please send any sales or price enquiries to sales@heatweb.com
Richard Hanson-Graville
Technical Director
Dedicated Pressure Systems Ltd.
All the advantages, None of the disadvantages.