Fully pumped hot water replacement

[Brianb]

I fitted a whole house pump a few years ago, which as the name suggests pumps hot water to all outlets in the house. It also pumps cold water from the loft tank to the shower to balance the unit. This system works well to a point i.e. good hot water flow which provides a good shower (Newteam Shower panel Diva-T, requires 3 bar) and can fill the bath quickly. We have a standard indirect open vented DHW cylinder and cold water tank in the loft raised about 1meter. The problem is the first pump only lasted 2 years and this one is noisy and getting worse. So what can I replace it with that will provide the amount of water pressure that's required for the shower panel. I've read just read the thread on Thermal Store vs. Heat Store, but can't say that I fully understand how each works. How do these differ from a Pressurised Unvented HW cylinder such as these

If I wish to fit a new (bigger?) water tank, how do I calculate how much weight I can load on the floor (1st floor, joist and floorboards), or is installing a pallet type arrangement of 6x2 and flooring on top of the existing airing cupboard floor adequate over a 1m sq area?

For info I have just had the boiler replaced with a condensing BAXI 100HE system boiler, the CH system works fine and doesn't require any work.

TIA Brian

[Set Square]

a thermal store and heat bank are very similar, but they differ from an unvented cylinder.

The all provide mains pressure hot water, but they do it in different ways. In an unvented cylinder, *all* the hot water in it is at mains pressure - thus requiring no cold header tank. There are a lot of safety issues with this arrangement, and these tanks can only legally be installed by people with the right qualifications.

In a thermal store/heat bank, the hot water is at only just above atmosheric pressure (just like a conventional cylinder) but there is a large heat exchanger *inside* through which mains- pressure cold water passes on its way to the hot taps - getting heated as it passes through.

This type of installation is legally D-I-Y-able.

The store may possibily have yet another internal heat exchanger for heating the the central heating water - enabling the boiler to operate more efficiently than with a conventional system, since it can run continuously on full power until the store is hot, and then switch off.

See the FAQ at

more information.

[Vortex]

I've read just read

IMHO Everything you need to know about Thermal Stores/Heat Banks is here: