Help with new system

[Plumbing novice]

I am looking for some advice on a new hot water/central heating system.
I would like a higher water pressure system than is historically used in the UK and have been looking at an unvented 3 bar system.
The house has 2 bathrooms which will be used regularly and 3 further ensuite shower rooms.
I am looking at a new connection to the water mains.
The plumber has advised 2 x 250litre megaflow tanks but has introduced a break tank and pump prior to joining the unvented tank. I am unsure but think this negates the advantage of having an unvented system. He has said I would need a 50mm connection to the main to avoid having the break tank and pump. I would be very grateful for some advice.

 

[ChrisR]

First find out what the mains pressure in your area actually IS. The Water provider will give you a good idea if you ask with your postcode. It could be anywhere between about 1 bar and 9 bar. Any plumber worth his salt will have addressed the question.

Second - What are your "loads" - how many baths & showers? How many showers to be used together, or consecutively? What sort of showers do you want? A mains electric "shower" is 4 litres a minute, a very acceptable one say 10 - 15, and a huge head with lots of body jets can reach 60. Volume of the stores has to match.

A break tank + pump set with unvented storage is one way to go, commonly used in situations from large domestic upwards. The pump maintains the pressure in the cylinder, which can be higher than your mains supply.
A disadvantage can be that the pump can run at any time of day or night, so noise is an issue.

Oh and , what's the budget?!

 

[Agile]

A very important question is how many people live there normally? If there are occasional visitors at Christmas could some reduction in performance be tolerated in that time.

Its VERY expensive in initial cost and running costs to have a system capable of running five showers at the same time when they are never ever likely to be required together.

A 50 mm mains feed is likely to have quite a high standing charge and I find it difficult to immagine how you will agree to pay perhaps £600 per annum extra.

Tony Glazier

 

[Plumbing novice]

Thanks for the information.

The average pressure for my area is between 4 to 5 bar, although the standard answer given is Scottish Water are only required to provide a minimum of 1.5 bar. The most number of showers we would be happy to have running at once without compromising the system is 3. The guest ensuites would only be used at weekends/christmas so would be happy to tolerate reductions in pressure if they are being used.

I was not aware there was a standing charge per year for the 50mm connection. Am I correct in thinking the standard connection is 25mm? What is the connection above this one. It may be that i do not need 50mm.

At present we are concentrating on what is the most effective system for a 5 bedroom family house with a new connection to the mains rather than concentrating on budget at the moment.

 

[doitall]

32mm would be the norm for what you are asking and should eat 3 showers at 3bar.

Cost you say shouldn't be a consideration (£2-3K) for breaktank and pump set may change your mind.

As I said on SF its the norm for large installions, I don't consider yours to be large, in fact not even close, and in any case it's unlikely that all will be used simitaniously on a regular basis.

Another consideration I mentioned is the kitchen should be connected direct to the mains, so in effect you are installing 2 systems (cost again) further consideration should be given to power cuts which could equal no water without by-pass being built in.

http://img.photobucket.com/albums/v395/thescruff/Imgp0994m.jpg

For Tony the pump set is very quite and you would not know it is running under normal conditions, although like all pumps they can cycle with WC use and where posible WCs should be direct fed from the mains.

 

[Agile]

It was Chris who questioned the noise John.

Thames water have not updated their web site and show 2005 charges.

15 mm £46

25 mm £184

50 mm £736

Those are the combined supply/waste standing charges. Volumetric are about £1.50 mer cu m.

Its a bit vague because domestic properties can be charged the minimum 15 mm rate even with a larger supply pipe.

It al depends on your local supply company and their policy and the time if day and who deals with your application.

Tony