Are you looking to replace your hot water cylinder with a thermal store?

Then you’re on the right page.






For the perfect hot water system, go thermal store...


Mains-pressure hot water...from just £2,390...inclusive!*



We ONLY ever recommend thermal store mains-pressure hot water cylinders

Perfect replacement for old Gledhill PulsaCoil



Sizing guide:

160 litres (suitable for two people who mostly shower, or one person who bathes)

210 litres (suitable for 3-4 people with two bathrooms). Larger capacities available.



LimeStop 800 (guaranteed limescale inhibitor) £75. See

Drip £49

Timed hot water £49

If you wish to purchase a thermal store cylinder to install it yourself, get in touch with us.



Types of water heaters...

Conventional cylinders (hot water tanks) are vented cylinders. However, they only provide hot water under gravity pressure or from a pump (see our main page HERE). For a much better hot water system, mains-pressure water is now provided in virtually all new homes. There are two competing systems (apart from combi boilers). These are...

Unvented heat bank and vented Thermal Store

Both have advantages and disadvantages, and they work differently...


wpbc2497ad.png wpc3af9fe9.png


This is an unvented heat bank. The one on the right is a electrically-heated version. The one on the left is heated by a boiler. An unvented heat bank is popular with installers as it is relatively cheap to purchase. However, due to safety implications, it must be installed and serviced by a ‘G3’ accredited engineer. An unvented heat bank ‘banks’ the heated water for later use. As the name suggests, it is not vented and thus is pressurised. It therefore requires a pressure release valve - and is part of the reason why it must be serviced annually by a G3 accredited engineer. This can make the cylinder a bit more expensive to own. Also, when an unvented heat bank suffers from limescale, it doesn’t show until it’s far too late to do anything about it. The cylinder has therefore come to the end of its life. This can happen in as little as 10 years. With a replacement cost of £1,800 it would mean an annual cost of £180 to be added to servicing and maintenance!








This is a simplified drawing of a vented thermal store. It is slightly more expensive to purchase compared to an unvented heat bank, and is thus not as appealing to installers (quotations for install costs would be higher). However, it requires no annual servicing. A vented thermal store is not pressurised, and is usually fed with water from a storage tank that sits on top. This merely keeps the cylinder full of water which heats up and acts as a store of heat (‘thermal store’). When a tap is turned on, the water passes through the coil and picks up heat as it traverses the coil. It requires no pressure release valve, but it does need a thermostatic mixer valve to function. When a thermal store suffers from limescale, flow is restricted through the coil. This is evident, and the coil can easily be descaled for around 1/6th of the cost of replacing it. Thermal stores over 30 years old are sometimes seen.


We ONLY recommend vented thermal stores. Their advantages over an unvented heat bank outweigh a cheaper install cost, as long-term they are a cheaper way to provide hot water.






We use high-quality British

products wherever possible



The Electric Boiler Engineers

We are at 19 Cockney Hill, Reading. RG30 4HF

Call or text us on 0770 231 6157**

Or email us -




With regard to thermal store systems, the provided hot water flow depends entirely on your mains pressure supply. We can assess your flow free of charge in the RG postcode area. 20 litres per minute is recommended by us to be sufficient for a considerable hot water supply without being unnecessarily wasteful. Systems are limited at 3 bar pressure. If you currently don’t have a mains-pressure cylinder installed, and your current pipes are fed by a water tank in the loft-space, they would be subject to a 3-bar pressure when converted to carry mains-pressure water. We cannot be held liable for their integrity. Full limescale protection can be provided by a Scalgon LimeStop 800 at £75 - please see This will give you GUARANTEED and unrivalled limescale protection for two years. After that time it should be replaced - current price £75. Capacity of mains-pressure thermal store hot water system in prices quoted is 160 litres. You may require overflow protection (extra cost) if your current heater is not protected, but this is your choice. Alternatively, purchase a water-leak detector for less than £10 together with a drip tray. We back up our installation with a 5-year guarantee and ‘within 24-hours’ call-out protection. An annual check may be required to validate a manufacturer’s 10-year guarantee on some thermal store cylinders. A deposit of 50% is required five days before work commences – balance on completion. Free, no obligation quotations provided. If you choose us, you will be provided with a binding contract, and your rights as a consumer are respected and adhered to. You have the right to cancel your contract. Terms & conditions apply - set out on your contract.

*There may be additional charges if we have to arrange hired labour to lift your current cylinder out, and the new one in.  Price includes a fitted plug to an electrical socket.  There is a small extra charge if we have to ‘wire-in’ the electrical supplies.

Mobile phone rates apply when contacting us by phone.

Prices correct as of last website update - December 1st 2022 - and are subject to change.