Sizing of cold water tank

As mentioned in previous posts I have determined that I need to move a cold water tank from under the stairs to the loft, to get the head for a hot supply in a new upstairs en-suite. The loft is big, but the hatch is very small. I've found a long, thin 25 gallon tank that will just fit through the hatch. It looks like the old tank is 50 gals, and the HW cylinder is probably about 20-25 gals form a rough measurement and back-of-an-envelope calculation. Do I really need a 50 gal CW tank (ie 2 of the small 25's), or will a single 25gal one do ?
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

cold water tank from under

en-suite.
hatch.
about 20-25 gals form a rough

single 25gal one do ?
It depends how deep you like to fill your bath. Most baths are around 180 litre potential capacity - around 40 gallons. If you are happy to work to World War 2 austerity guidelines, you should be OK. Personally, I found that the 25 gallon tank I had in my house when I moved in ran out of water before the bath was full enough. I simply fitted a T-piece to the main outlet pipe from the original tank and ran that into the bottom of a second 25 gallon tank, doubling the storage capacity.
Colin Bignell
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

cold water tank from under

en-suite.
hatch.
about 20-25 gals form a rough

single 25gal one do ?

You cold water tank feeds the hot cylinder and a bath ? Or is there only a mains fed shower or something ?
The cold water storage tank should be at least one and half times the capacity of the hot cylinder, but then you also have to bring into the equation, any appliance which is going to draw more than the tank can supply on top of the capacity of the hot cylinder.
One question. Could you lie down in 25 gallons of water to have a bath ?
Depending on your answers to the above questions, then it is better to have to much, than to little. You don't want to go dry to quickly is there is water burst on the mains supply in the street. It's comming into winter remember.
If you're fitting the two tanks, try to have one as the feed in and the other as the draw off, and make sure they are connected together in two low down positions, with the largest bore pipes you can possibly get (50mm plastic waste pipe is the ideal). I say this because, the legionaira (spelling) bug thrives better in standing water, so what you need is a continuous flow from one tank to the other to keep all the water moving in both tanks.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

Tank would feed hot tank and bath (although cold feed to bath could in principle be from rising main, I guess it would be coming in colder and therefore need more hot...)

I have no idea.... of course the bath would be a mix of hot & cold...

I figured that feeding into one and out of the other would be the way to do it, but can't see how having the interconnect any thicker than the outlet, or more than one interconnect would make any difference... any clues ?
How easy is it to get suitable fittings for plastic waste that will seal reliably to a tank..? I assume the tank is polythene or polyprop, so solvent would be out, and I'm a little sceptical about compression using plastic pipe... any suggestions ?
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

upstairs
a
principle be from rising

supply
have
low
in
do it, but can't see how

interconnect would make any

This helps prevent build up of scum and small debris from blocking anything to narrow, and also allows the water to swirl around as the tanks fill, so keeps it on the move as much as possible. Safer.
The point is to allow the least possible resistance to the flow of water between the tanks. Ideally, if the tanks are side by side, they would be connected with 1 X 2'' (50mm) pipe as close to the bottom as possible, which helps if the tanks have to flushed out at any time, which they will, and 1 X 2'' about half way up the full water level. This makes the water in the primary tank (feed in) to cause the water in the secondary tank to swirl at two points, and also keeps the water level balanced in both tanks.
As water is fed in and drawn off, you don't want to get the draw off tank dropping its level to much before the feed tank can keep it replenished.

reliably to a tank..?

I'm a little sceptical

Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
Mike Harrison wrote:

Yes, if you take the cold supply directly from the mains, ensure that the feed to the tank is 22mm and as straight as possible, and you have good and reliable flow from the mains, a smaller tank will do. The only consideration is whether the cold feed to the tank can keep up with a reasonable rate of draw to the bath.
My bathroom is fed from its own hot water tank (immersion heater) and supplied from a 5 gallon! cenral heating feed and expansion tank.
Nick
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
Mike Harrison wrote:

Hi again Mike
My B&G catalogue has a 3-part 50gal tank, each segment 24x18x15 (I think, I don't have it to hand now!). That would already have all the fittings, etc you need, such as the by-law kits.
If it comes to coupling a pair of 25gal ones togther yourself then most merchants will have 28mm tank connectors for a couple of quid. You'd thne need a short length of 28mm copper tube.
HTH IanC
PS: Let me know if you see this due to the earlier no show of my message from this server. I think its a matter of where your NNTP server is peering with, since it did appear on Google. If your server is poor it may be worth Googling to look for answers to the your own posts, so you miss fewer.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
wrote:

Do you have any info on make/ price ? What's in a by-law kit - I've seen them mentioned on some sites - presumably the bits to make it comply with by-laws but what does it typically include ?

Received OK!
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
Mike Harrison wrote:

Polytank, over at http://www.polytank.co.uk . But I can't see the item on the web site. Maybe they've stopped doing them?
You could also call B&G (http://www.bandg-heating.co.uk ) to see if they can help you. They're usually pretty helpful with queries.
Price in the B&G catalogue (couple of years old) is 86+VAT.

To comply with water bye-law 30, IIRC. Not sure of chapter and verse, but its things like a lid, insulation, filter on the breather hole, etc. Not rocket science, but all making for improved 'reliability' of what's in the tank.
HTH IanC
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

Hi Mike
Did you see my suggesition re the round polythene ones? You can squash it down, put some tape around it and it should fit though the hatch.
Once in, remove tape and the water will return it to shape once filled.
IanC
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
On 30 Sep 2003 07:03:36 -0700, clowes snipped-for-privacy@hotmail.com (Ian Clowes) wrote:

No I didn't (I'm using a possibly flaky NTL newsfeed!) - not sure if one of these will go small enough - hatch is 12 x 20", but will investigate next time I see one.

Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
Size of take will depend on: Your individuals requirements....How many people in household if you live alone then 25 gallons should be ok. If you have a full household and more likely to have more than one appliance running at one time quite often...You`ve gussed it!!
If you are worried about losing head pressure have you considered a pump, positioned on your flow pipe.
One tip though Please make sure your inlet is always one pipe size larger than your outlet pipe as you do not want tank to run dry.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
On 01 Oct 2003 21:19:59 GMT, snipped-for-privacy@aol.com (Keithc666767117) wrote:

Surely the fact that the inlet is at higher pressure would compensate for this ?(assuming you have decent mains pressure by the time it gets up to the loft..!)
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

Related Threads

    HomeOwnersHub.com is a website for homeowners and building and maintenance pros. It is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.