Mains hot water pressure without a Combi or Unvented system

[countmore]

Hi, I was wondering if someone could help me with this odd question.
I have a 4 bedroom house with two showers and wish to change my heating system but I do not want to have a combi or unvented system. At the same time I wish to have hot water for two showers without a pump. I have looked at thermal storage system but it is far too expensive.

Is it possible to install a hot water tank with two coils inside? (I know they are available to buy).
One coil working as normal heating up the tank from the boiler. The other coil however connected to hot water taps and acting in reverse. Ie: Cold water from the cold water mains going in to the second coil in to the tank and coming out the other side hot.
This method will give me hot water at mains pressure (drinkable) and thus providing both showers/ kitchen sink and bathroom sinks with mains pressure hot water.
The water in the tank itself will never leave the tank. It will have a small header tank in the loft, unvented.
Basically its just like a thermal storage system but a home made DIY job at much cheaper price.

Could any of you experts out there tell me if this is possible?
Many thanks
Sean

 

[simond]

Either you are a genius or the rest of the heating trade are idiots.

But seriously, what you have suggested is an old idea and does not work particularly well. However there are/were a few commercial versions.

I recall Albion used to make a cylinder incorporating a shower coil and there was also a copper coil that could be inserted in an immersion heater boss called Sidewinder.

There are different qualities of thermal store and the cheaper ones such as Gledhill Torrent (I think Albion also make a basic one) may suit your budget better.

 

[bobthebender]

Hi:
What you want is available or you can knock up your own using an external heat exchanger,pump & flowswitch.Try these links.

http://www.heatweb.com/pdf/DPS/White Box.pdf

http://www.albionwaterheaters.com/pdfs/sales/mainsflow.pdf

 

[countmore]

Hi:
What you want is available or you can knock up your own using an external heat exchanger,pump & flowswitch.Try these links.

http://www.heatweb.com/pdf/DPS/White Box.pdf

http://www.albionwaterheaters.com/pdfs/sales/mainsflow.pdf[/QUOTE]

Thank you very much for both posts as it has been very helpful.
Do any of you have experience as to how well the heat bank works?
I am talking about the separate heat bank that can be added to the normal tank that i already have (from your link)
Does it give the same temp of hot water as i am getting now and feed two showrs?

 

[bobthebender]

what do you plan to use to heat your cylinder/s ?

 

[countmore]

what do you plan to use to heat your cylinder/s ?

At the moment i have the standard vented heating system with a tank. I

Hi, sorry, have just come back from work.
I have a shower room and a bathroom with a shower on top of bath. Up to now i have been using one elctric shower above bath and a pump for the shower room.
I am going to change the boiler to an updated one and so thinking of coming up with a better system than i have now.
Problems are
Pump is noisy and can be heard all over the house
Changing my electric shower requires me to update the fuse box as well as changing my 6mm cable to 10mm (that'll be few hundred pounds including a new electric shower)
Combi boiler is really not suitable to run two showers. Its really a one outlet system. THe amount of times we keep opening and closing taps will run down the combi in no time.
Unvented system is very expensive to repair
etc etc etc
---------
So i was thinking of a way to have two showers to run at a good pressure. I am not concerned about kitchen tap or bath as the pressure would be fine under gravity.

This is why i came up with the idea above but then you said that the system already exists in a different way. So i checked your link and it came up with Heat bank (I read somewhere that they are about £150).

I just want to run two showers with good flow without the problems of pumps, major electrical work etc.
Thanks

 

[simond]

I don't really understand how you can 'run a combi down', yes, you can usually only run one outlet at a time, but they are installed in many a 4 person family without problems.

And I am also surprised about the 'unvented system being expensive to repair'. Where are you getting these ideas from, they are unfounded. An unvented system should go for years without repair, there is virtually nothing in one.

 

[Corgigrouch]

There is very little to fail on an unvented, a heat bank on the other hand can be a pain in the backside, especially if the name on it starts with Gled and ends with hill..... I'm not too sure that you could run two showers off a heat bank either as it would still rely on a heat exchanger...

 

[Norcon]

If you have an existing vented cylinder then keep that and add a good sized plate heat exchanger.
You can buy them on e bay. I paid around £300 for their 30 plate/0.9 which is a huge heat exchanger. Stokvis and BSS were looking double that for the same stainless steel.
All you need then is a bronze circulator and flo switch.
And if it breaks down you still have hot water.

 

[countmore]

Thanks for comments.
It will cost me around £1500 to change my boiler. My tank is newish. If i were to change it to unvented, then the costs will double. In addition after talking with two people with unvented systems with some problems, i have come to the conclusion that maintaining the system in tip top condition in the long run will be costly. I have seen small leaks costing a few £100s to fix.
Anyone can fix a leaky vented tank but not an unvented one.

I would lkie to know if anyone has experience with an external heat bank next to the existing tank and does it work well in running showers?
many thanks

 

[countmore]

If you have an existing vented cylinder then keep that and add a good sized plate heat exchanger.
You can buy them on e bay. I paid around £300 for their 30 plate/0.9 which is a huge heat exchanger. Stokvis and BSS were looking double that for the same stainless steel.
All you need then is a bronze circulator and flo switch.
And if it breaks down you still have hot water.

WOW, do you get enough hot water for shower with good pressure?
I will look in to this tonight. Do you have a name for the exchanger?
many thanks

 

[Norcon]

I should point out I used this heat exchanger on a small biomass project which is currently operational.

Slightly different from DHW supply on a vented cylinder but the principles are similar.
Heres a link to the exchanger....
http://alturl.com/38e98

To run two showers concurrently your cold mains supply needs to be adequate.

 

[Norcon]

Hi:
What you want is available or you can knock up your own using an external heat exchanger,pump & flowswitch.Try these links.

http://www.heatweb.com/pdf/DPS/White Box.pdf

http://www.albionwaterheaters.com/pdfs/sales/mainsflow.pdf[/QUOTE]

I think dps are going into administration next week.

 

[simond]

Crikey that would be a shame, they had a few very bright people there.

How do you know?

 

[Norcon]

An e- mail posted up on navitron.