Need help plumbing in shower!

Rob · 27 Feb 2009

Got an electric shower (in pic) fitted to the mains but being in a block of flats 8 floors high the pressure isnt great and the shower has never worked.

Now its a favour sort of job just to get it working so minimal work is the idea.

Propose to feed the existing electric shower from a 1bar single impeller shower pump which is taken from the (pretty small) CWSC.

No access to tank to fit additional cold feed so was wondering if I could tee off the feed to the cylinder. like this.....

As i said it doesn't need to be perfect it just has to work.

Cheers

ChrisR · 27 Feb 2009

The risk is always of stopping the water flow out of the HW cyl down the red pipe. It'll probably work ok but you won't know until you try. Depends on pipe lengths, heights etc.

Rob · 27 Feb 2009

You mean whilst the shower is running no HW will flow from anywhere else? Shouldn't be a problem.

And its literally all there. Tanks are in the same cupboard on the landing and shower is on other side of the wall. Is this ideal

ctp · 28 Feb 2009

tap directly into the cws tank

Rob · 28 Feb 2009

ctp said:
tap directly into the cws tank

Not possible

Stivino · 28 Feb 2009

What about teeing into the supply to the cistern?

Rob · 28 Feb 2009

Stivino said:
What about teeing into the supply to the cistern?

Thats the way it currently is but the mains pressure is so poor.

Is there any majot problems with what i suggested?

Stivino · 28 Feb 2009

What about teeing into the supply to the cistern? And use your pump?

electronicsuk · 28 Feb 2009

Stivino said:
What about teeing into the supply to the cistern? And use your pump?

Sounds like a bad idea to me, pumping mains supply water and all

In any case, if the incoming pressure is low and the CW header tank is small, exactly what benefit is this system going to provide? The CW header is only going to act as a break tank, so unless the occupant only takes very quick showers, the tank will soon be empty and unable to refill as fast as the shower is consuming water.

And, on top of that, why are you bothering to pump an electric shower when you have a tank sitting there full of hot water?

Rob · 28 Feb 2009

electronicsuk said:
And, on top of that, why are you bothering to pump an electric shower when you have a tank sitting there full of hot water?

So whats your suggestion?

If i were to fit a thermostatic shower and pump hot supply where does the cold come from bearing in mind i cant fit extra CF and the mains pressure will be less than the pumped supply.

electronicsuk · 28 Feb 2009

rob884 said:
electronicsuk said:

And, on top of that, why are you bothering to pump an electric shower when you have a tank sitting there full of hot water?

Click to expand...

So whats your suggestion?

If i were to fit a thermostatic shower and pump hot supply where does the cold come from bearing in mind i cant fit extra CF and the mains pressure will be less than the pumped supply.

It doesn't solve the problem at all. However, it makes more sense than having the 7-10.5kW load of an electric shower when you already have a tank full of hot water sitting there. You would need to take the CW supply from the header tank to provide equal pressure at the pump, although in your case, with not being able to get at the header tank, this would mean tapping into the cold feed for the HW cylinder. Whether or not this will provide the performance you need is going to depend on the size of said feed.

However you go about it, you will still have the same problems with low pressure. My suggestion would be to increase the size of the header tank, then run a pumped shower from the HW cylinder. This will offer the best performance, and with a large enough tank there will be no worry about running dry.

However, as you can't get to the header tank, this job seems like a non-starter. It seems your best hope is that the existing tank is large enough to support the increased flow rate of a pumped shower, but if that turns out not to be the case, you've completely wasted your time.

swidders · 28 Feb 2009

How high above the intended outlet is the water tank?

Are you sure that the pump is being fed off the mains? It may be that the kitchen has mains pressure but that the bathroom and it's own cold water tank is fed from a larger cold water tank at the top of the block of flats.

mogget · 28 Feb 2009

OP - electric showers don't tend to have high flow rates. I'd have thought that as long as the cold feed to the cylinder is 22mm or above, and the existing system is capable of filling a bath, your original suggestion will probably work OK.

You may find that you can't draw much hot water from the cylinder while someone's in the shower. Lots of people have the same problem with gas combi's, and they cope ok.

What I don't know is whether you'd be breaking any regulations.

Whitespirit66 · 28 Feb 2009

Stivino said:
What about teeing into the supply to the cistern? And use your pump?

Pumping from the mains supply is against water regs. - not saying that it doesn't happen though!

Also, the layout that the OP suggest, pumping from the CW supply to the cylinder is also in danger of drawing hot water out of the cylinder.

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Need help plumbing in shower!

swidders

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