Re: Cylinder v thermal store

[IMM]

I've been looking at the options for re-plumbing my place and have been

> looking at the Telford products. I want to do a mains pressure system but > I'm a bit confused about the difference between the Tornado Unvented > Cylinders and the Tristor in the TSS configuration. > > What are the effective differences between the two systems, seem very > similar to me? and what are the advantages and disadvantages. > > Heating will be by oil fired boiler. probably a Danesmoor (spelling?). > > The house is four bed, two bath, two story. approx 11m square (approx 240m2) > with 2.8m ceilings downstairs, normal 2.4 upstairs. > > Chris

The Tristor is a solar thermal store. This is quite different to the Tornado unvented cylinder. It uses mains pressure water for the whole house, but the operation is fundamentally different to an unvented cylinder. An unvented cylinder cannot be DIYed, a thermal store can.

[IMM]

Chris

What are you intending to do.? What size house, etc, etc?

[Chris Harris]

hmmmmmm Rubbish. I know plenty of people that have DIYed an unvented cylinder. It's just plumbing, as an old plumber once said to me "all you need to know to be a plumber is that SH*T stinks and P*SS runs downhill".

Appologies to all plumbers who will know doubt take offence, none intended.

Admitedly there is a bit more to an unvented system than that, but not a lot.

The thermal store in the brochure, under the TSS system is unvented. Fair enough if it's meant for storing solar heated water.

Chris

PS if you had read to the end of my msg. you would have been able to see what I want to do and the size of the house.

[IMM]

Not so.

You have to be BBA approved to fit an unvented cylinder. Do it yourself by all means and if you have a burst, and when they go they really go with much damage, an insurance company will not touch you. With most you need an annual service. Once again, no service, no pay out.

He referring to drains then, which plumbers are good at. Heating appears to have flown past most of them.

Once again, a thermal store can be pressurised (unvented) and this has be fitted by a BBA approved fitter/plumber. There are vented thermal stores, the most common, and these can be DIYed.

What are you doing to the house? Do you want tanks out of the loft, the thermal store in the loft to make more space? ???

Go for a vented heat bank, not a thermal store, much better than an unvented cylinder.

(to th thermal storage)

[Chris Harris]

Not in this country. What is BBA?

I plan on fitting a Danesmoor diesel boiler, a 32/50 (or is it a 36/50? don't have the details to hand) heating an unvented mains pressure system suppling the kitchen, one bathroom downstairs, one upstairs. The boiler will also provide the heating via radiators.

There will be no tanks in the loft with an pressurized system, but that is not an issue as there is plenty of space.

I'm going with what I know and what is available locally. I was and am curious about the difference between the thermal store, heat bank, and unvented cylinder or indeed a vented cylinder. They all store hot water and seemingly there is not much difference. The insulation specs are similar the actual plumbing arrangement is similar.

I'll take a look. Chris

[Chris Harris]

Right I've been looking at the sites that you gave me and could see the difference at a glance, something that the brochure from Telford didn't (doesn't) show :-)

So in reality; what do you see as the practical day to day advantages of a thermal store system over a standard mains pressure cylinder?

What are the relative costs, in materials only?

[IMM]

Stop trying to be know-it-all. In the UK you need to be BBA approved to fit a pressurised cylinder.

There is a big difference. A heat bank and thermals store instantly heat incoming mains water. The stored water is "primary" water and is heated by the boiler. It is the same water, generally, as the boiler water and will have inhibitor in it. A thermals store has an immersed coil and a heat bank uses a plate heat exchanger with higher flow rates.

Both thermal stores and heat banks can provide the CH from a flow and return taken off the bottom of the cylinder. These are called "integrated" stores. There are also DHW only stores and heat banks.

An unvented cylinder is similar to vented cylinder, except is used high pressure mains water, while a vented uses low pressure water from a cold water tank.

It is best you use a vented thermal store

the Mainsflow) or heat bank (see DPS or Range) as these can be DIYed. Some heat banks don't even need an overflow, so can be fitted in the centre of the house.

Range and Albion products are available from most plumbers merchants.

[IMM]

A heat bank:

- gives higher flow rates.

- operates on low pressure.

- can be DIYed.

- eliminates inefficient boiler cycling, so cheaper to run.

- Fast re-heat

- does not have an air bubble that requires reinstating every year

- does not require an annual service.

- Can provide CH and DHW from the same cylinder

- Can be packaged all in one unit (you just connect up pipes to the boiler and rads, with no design work involved)

- Hot water temp at the taps user selectable

- A heat bank does not scale up.

- Can have electric backup for CH and DHW when using an integrated heat bank or thermal store.

A DHW only heat bank/thermal store is less than an unvented cylinder.

[Chris Harris]

Same to you. I don't live in the UK, check my eamil address. So not in this country is a fact!

Thanks for taking the time to explain that.

Now if I have the boiler downstairs along with the heat bank, and the CH is taken off the cylinder, which is unvented, I can't have radiators upstairs?

Can the radiators be feed from/through the heat exchanger? Or alternatively I guess you pressurise the storeage cylinder as for an unvented system?

Chris

[Chris Harris]

Very interesting. I'm going to have to do more research on this. Sounds too good to be true. What are the disadvantages.?

Chris

[IMM]

This uk.d-i-y. What country is fk? Falklands?

DIYed.

With a vented the rads have to be below the heat bank, with an "unvented", or pressurised, heat bank the rads can be anywhere and the heat bank can be anywhere. Most have a vented heat bank on the first floor, which is above all rads.

If it is pressurised, then the rads can be taken off the bottom of the cylinder.

Best go for a DHW only heat bank or thermal store with a boiler heat transfer coil. Have the CH circuit pressurised. Then the heat bank can located anywhere and rads anywhere.

[Andy Hall]

There's no need to be rude.

- I don't believe that Chris is in the UK....

- In the UK, the position appears to be as follows:

From the Building Regulations, 2000

Hot water storage

******************** G3. A hot water storage system that has a hot water storage vessel which does not incorporate a vent pipe to the atmosphere shall be installed by a person competent to do so, and there shall be precautions -

(a) to prevent the temperature of stored water at any time exceeding

100°C; and

(b) to ensure that the hot water discharged from safety devices is safely conveyed to where it is visible but will not cause danger to persons in or about the building.

********************

Note that there is a requirement for competence without it being defined, just as in the Gas Safety (Installation and Use) Regulations.

From the Approved Document to Part G:

The unit or package should be installed by a competent person, i.e. one holding a current Registered Operative Identity Card for the installation of unvented domestic hot water storage systems issued by

a) the Construction Industry Training Board, or

b) the Institute of Plumbing, or

c) the Association of Installers of Unvented Hot Water Systems (Scotland and Northern Ireland), or

d) individuals who are designated Registered Operatives and who are employed by companies included on the list of approved installers published by the BBA up to the 31st Dec 1991, or

e) an equivalent body

Notably, this says "should" and not "shall".

The IoP maintains one of the Competent Persons schemes allowing self certification as opposed to a Building Notice.

The Statutory Instrument does not appear to preclude submitting a building notice

.andy

To email, substitute .nospam with .gl

[IMM]

Rude? The man was terse.

he should have said so. And he still didn't say where he was.

[IMM]

Show us.

[IMM]

Did you contact them and find out?

[Chris Harris]

Yes, which is UK overseas territory. As all our systems here are UK standards, and most products imported from the UK it makes sense for me to participate in a NG that is relevant to those standards and products.

You are participating in a NG that is open to the whole world, you shouldn't make sweeping asumptions that just because the title of the NG includes UK that all participants are located there. I've seen postings here from all over.

I don't see why I should state my location, as you suggest in another post. My question was what are the differences between certain products, not who or what should install them. Therefore the location is irrelevent.

[geoff]

In message , IMM writes

Er, if the recovery times don't give the starting temp, what is there to show, logicboi?

[IMM]

They have a rig in their place that they allow customers to test. You can always go their and take measurements yourself.

[IMM]

It is uk.d-i-y. the onus is on you to state you are not in the UK. The southern Ireland posters do that, and their standards in most things are not far off ours.

[Chris Harris]

Ok fair enough you have made your point, and point taken. But the onus is on you to answer the question and not to preach who can and can't install any system. The rest of your comments have been very useful.

Now I've been doing a fair bit of reading today, and thinking where I could put in an unpressurised heat bank. Might be able to squeeze one into the back loft, definitly could get anything in the main loft.

Does anybody do a design service? Or more to the point who does a good fair, unbiased, design service?

If I'm going down this route I would like to have at least a plan, if not a materials list, drawn up by a pro. As I will be importing almost everything, either because I have to or just to save costs, I would like to get it right.

Chris