Dedicated pipe from HW tank for shower?

[John]

Does a shower which will be supplied from a HW tank and mains fed cold water always require a dedicated connection to the HW tank? The HW tank is located in the basement and the cold storage tanks are in the loft (i.e plenty of head). There will be a shower in the basement near the HW tank and there is currently a 22mm pipe off the HW tank which runs pass the location of the proposed shower to the bathroom above (where it feeds a bath, sink, shower[not installed yet]). Would it be more appropriate to run a new 22mm pipe from the HW tank for the two new showers and nothing else?

John

[BigWallop]

With mains fed cold water to all the taps, then you'll need as much flow of hot water to the showers as possible. I'm assume the showers are mixer valve style. In the winter months, the cold water supply will take a lot of heating up, and this might take a lot of the pressure out the shower head because the cold supply will be almost turned off.

If the one 22 mm pipe is feeding all the other appliances, then will, or is there a chance that, the other appliances will be used at the same time as the showers ? Like if someone is in the shower, will anyone else be able to run the hot water in the wash basin ?

You will need as much hot water going to each appliance as you possibly can, so if this means taking a separate supply pipe to each appliance, then this is the best solution.

[Tim Mitchell]

In article , John writes

The problem comes when someone else uses hot water from the same pipe as your shower, causing an unpleasant cold sensation to occur.

If you think this is unlikely to occur, or you're prepared to live with it, then you could use the existing pipe.

You might also want to feed the shower cold from the cold water storage tank rather than the mains, otherwise if anyone in the house uses cold water the shower can get very hot very suddenly.

[John]

How is this handled at the feed out of the HW tank, presumably you would have one surrey fitting with one or two 22mm feeds off this?

Thanks John

[IMM]

John,

The shower must have its hot water from the cylinder and the cold from the tank, unless you are fitting a venturi shower, which can have its cold from the cold mains and hot from a low pressure cylinder. Here is an explanation:

[IMM]

No. Have a separate 15mm pipe for each from the cylinder.

[BigWallop]

If you've ever been in a gents toilet where the trough is rinsed by a pool pipe, then the concept is the same. One large pipe feed lots of smaller pipes. So if you take the largest diameter pipe as close to each appliance as possible, then the appliance is able to take the flow it needs without being to restricted.

[John]

Thanks Tim, Is this the case even with modern 'thermostatic' showers around these days?

John

[IMM]

yes, but less so. the thermostats don't react fast enough.

[Tim Mitchell]

In article , IMM writes

Nowhere near fast enough. You can still get your botty burnt or frozen. I speak from experience here. It will adjust back to the right temperature within about 5 seconds, just in time for the other person to turn the water off again, then you get the opposite effect. You can usually tell by the noises emitted from the shower user whether it has been a cold/hot experience or a hot/cold one.

[The Natural Philosopher]

Yes. If you want best flow rate and lack of interaction between all the bits and pieces.

[Mungo Henning]

Why mains cold and tank hot? That's what I found when I moved into my present house and the variations in mains cold pressure made it a b*gger to set the right temperature even on a thermostatic shower.

How about cold-tank cold and hot-tank hot?

When I moved my hot tank some time ago (google will archive all the tribulations about the move) I replaced the 22mm feed to the tank with 28mm, and also replaced the 22mm draw-off with

28mm which then descended a couple of metres to a T-piece where either side was 22mm. Thus there is bit more current down to the tank to keep it supplied, and you don't notice any other draw-offs when you are in the shower.

Just my experience.

Mungo