moving HW cyliner into the loft?

It is a 180 litre DPS Pandora heat bank. It never runs out when running a shower, because it is being replenished by a 28kW boiler faster than a shower can take the heat out.

A crappy 1970s style storage system has a small unmodulated boiler attached to a low transfer coil and, so, have limited recovery performances, which is why you run out. Using a modern modulating boiler and modern storage system, this is no longer the case.

Christian.

Subject to mains pressure being adequate this would be true of a 28kW combi too. I would agree that the storage would be useful if mains pressure was an issue or you ran baths at all often.

Of course any storage system will run out if the boiler isn't firing. But with a fast recovery type and a decent boiler it will be re-heating the store just as fast as some combis can manage to heat the water directly. And many better combis include a store to make use of this principle - except that it is a smaller store, with the limitations that implies.

Not surprisingly, a 'standard' storage system should be designed to give you a large bath full of piping hot water and fill it in a reasonable time.

When a heat bank is connected directly to a boiler (no intermediate coil), and a blending valve is fitted to the boiler to ensure 75 to 80C water only enters the cylinder, the heat entering the top of the store of water is immediately extracted and pumped into the DHW plate heat exchanger. In short acting like a combi does. It has two flwrates. The fast one using the store of water and the slow one using the power of the boiler when the heat is exhausted in the store.

Exactly, or just go straight to a combi and cut out the unnecessary cylinder crap if baths are not used that often.

Indeed. However, it doesn't take a combi to provide continuous hot water. A storage solution also does this provided the output taken doesn't exceed the usable boiler power long enough to exhaust the storage.

Combis don't have a monopoly on continuous hot water supply.

Although most combis are mains pressure and some storage systems are cold cistern based, there is actually no direct mapping between them. Combis can be run off a tank. Storage systems (including mine) can be designed to run off the mains.

Christian.

...and the boiler output is taken directly to the DHW.

Many people have combis off a storage tank to eliminate the cylinder to gain more space or create a shower cubicle. It also has the advantage of the stored cold water being at a higher temperature than the cold mains at times, giving a higher flowrate.

I have put combis off cold tanks with a pump giving higher pressures for showers. I have a combi off a cold tank, which gives 1 bar pressure. The pressure is always constant to the point I never used a thermostatic shower mixer, which makes matters simpler.

A combi runs out sooner, though!

Christian.

You don't say! Wow!

How sad. This senile one actually believes that.

;-)

Seems I'm not the only one either. See Christian's posts. But of course you can't find specs in any of your catalogues so it can't be true.

Remind us once more of your qualifications? You seem to have positively no idea about how things work or be able to do basic calculations.

Do most at the clinic believe that too?

I did and he didn't say what you said.

Of course he didn't. Unlike you he doesn't just quote other's work so of course it won't be word for word. However, anyone with even half a brain would realise the conclusion was the same.

Ask your nurse. She will be used to explaining things to dribbling idiots.

I know, I read it. How was the cauliflower cheese tonight?

============= It depends on circumstances and personal preferences.

The first one I had was built in to a new house which had no CH until I installed it and it was just convenient to preserve the unlimited HW facility.

My present setup was a matter of expediency. The house I bought was in need of considerable renovation and I had to renovate and live in it at the same time. The CH had been condemned and the HW tank leaked slightly when the immersion heater came on. The quick and easy fix was to install a multipoint, and it seemed logical to leave it alone when I installed the new CH.

And of course, I happen to be one of the people who like multipoints. I'm aware of their limitations but as long as it provides good service with no major problems I'm very happy.

Cic.

If you use pressurised hot water system you don't need the cold water tank, but you may need a new boiler..that is certified to run with pressurised primary circuits.

The tank will be expensive, but IMO its worth it. It will need safety pipework running to insulated overflows dumped outside in a safe way (can blow of steam at 100C or more under fault)

My tank is like this and its in the loft too. Things I would do if I did it again are few - maybe make an insulated cupboard around it...it gets very hot, and its own insulaton is not enough to prevent quite a lot of heatloss on a cold night.

I've also boxed in most of the pipes to it - they are insulated with foam covers - but I added rockwool around them as well.

Do run te immersiion heater to not only an isolation switvch nearby...but also to a remorte switch that means that you can run it in summer or emergencies withiut having to crawl into the loft.

Having said that, I use the boiler for hot water all year round, rather than immersion.

well its obviously drivel, in case his existing ISP closes his account..

The cost of doing what he said obviously exceeds the cost of either a decent high output combi, if there is such, or a proper large pressurised tank installation. I mean, Drivel is always one to spend £2 to save 50p isn't he?

The ISPs line to take me. They keep sending me letters and emails.

Much botty talking going on here. An Alpha CD50 is £912 on uselessenergy. This delivers about 20 litres minute. Two is £1824. That delivers 40 litres/min, no tanks or cylinders. It also has natural zoning, so one does upstairs and one does down.

Show me a two zone system that delivers 40 litres/min with mains pressure at the taps and never runs out of hot water that is less than £1800 all in, except the rads and pipe.

Show me a standard domestic water main that delivers 40 litres per minute.