Moving CW tank

[Mike harrison]

Couple of quick questions for those familiar with plumbing regs....

I'm moving a cold water tank from under the stairs to the loft.

Do I need to run seperate outlet pipes from the tank to the hot cylinder and to the cold taps, or can I just tee off the hot cyl feed from the cold tap pipe (This would save me an extra pipe run)

Is it necessary to have the ballcock and outlet on opposite ends of the tank to get circulation, or can they be on the same side ? It is a 'coffin' style tank, about 18x18x72"

Thanks for any advice to this occasional plumber...!

[BigWallop]

And here:

[BigWallop]

Sorry !!! :-)) I've replied to the wrong thread again.

I'll get me coat. :-))

[BigWallop]

You'd have to make the single supply pipe a much larger diameter for it to properly supply both systems. The reason these systems have two separate pipes is the fact that they normally supply the same amount of taps on each. So for the tank to able to maintain the same volume of water to each system, the pipework needs to be the same on each, therefore, you'd need a much larger diameter on a single pipe supply, than you do on a two supply design.

Hope that makes a bit of sense. :-))

[Andy Hall]

I don't know that any regulations apply to this aspect, but it would be better to have separate runs IME, otherwise you will find interaction between hot and cold tap flows when you run them.

There should be a sheet of instructions with the tank. You should have a Byelaw 30 kit with the tank, or get one. This consists of various components such as a screen to prevent creepy-crawlies entering the tank through the overflow, an insect proof screened vent to allow air in and a small syphon tube for the overflow.

There is no particular requirement regarding fitting of outlets in relation to the float valve.. However it is a good idea to position the outlets at different heights. The outlet to the hot cylinder should be slightly above those for the cold taps and shower(s). That way, if the tank empties, the hot water stops flowing first. The other way round and you could be scalded.

.andy

To email, substitute .nospam with .gl

[BillP]

It is recommended that the inlet and outlet be at opposite ends of the cistern to ensure the best exchange of fresh water through the system. even more important on coffin cisterns. Having the outlet below the inlet at the same end can lead also lead to air being drawn into the system.

Bill

[Mungo Henning]

Hi Mike,

I upgraded our loft supply to the hot tank from 22mm to 28mm (and had to change the fittings at the hot tank too). This was in order to deal with the case when someone uses a hot tap whilst the gravity shower is being used. I'd run separate pipes (slightly more hassle, but you are in for hassle anyway).

Yes, to reduce chances of "stagnation". Close fitting lid too.

Also, the outlet for the hot tank to be higher on the storage tank than other outlets: so that when the mains supply goes off for some reason the person in the shower isn't scalded since the hot tank runs out of supply before the cold supply to the rest of the house.

HTH

Mungo

[Mike Harrison]

I didn't think of that.... I was probably trying to think too hard about syphonage etc. to reaslise something obvious like that..!

I've got all that - the leaflet shows ballcock and outlet on opposite sides but doesn't mention if it's a requirement or not,

Good suggestion!