Shower Pump or Electric Shower?

[HarpingOn]

We have a 10 year old weedy gravity fed mixer shower, in the en suite (top floor).

The top floor contains also the cold water header (in the loft) and the hot storage tank (airing cupboard, same level as the shower).

The gravity fed mixer is weedy, and after 10 years we're fed up of the dribble, and want more of a gush. Doesn't have to be ripping yer skin off, but something with more oomph.

As far as I can see, I have two options.

Take out the existing shower and install an electric one. There is no electricity supply in the en suite beyond the light, fan and shaver point. A new supply cable would be needed.

or...

Put in a shower pump for the existing mixer. I think the feed comes from underneath the hot water tank in the airing cupboard. The central heating pump is under there. Might be a good place to install a shower pump too?

Will a pump be compatible with our antideluvian unknown brand 10-11 year old mixer, or will it blow it to bits?

I agree that neither of these are DIY jobs, not for me anyway. But I'd like to be as clued up as possible before engaging tradesmen for quotes.

[Davey]

I have a similar project, and we have already had the local plumber come and take a look. He says to put a pump, with dedicated supplies of hot and cold, under the tub. There is room behind the false facing of the tub to hide it. We need a power supply pulled to it, as there is none anywhere near. And since the weedy shower head/mixer is old and useless, we would replace that lot anyway. We don't have a time planned for this yet, so I will be watching your postings with interest.

[Andrew Gabriel]

You will get a better shower using a pump, which will almost certainly work fine with your existing mixer. The hot water take-off will be from the top of the cylinder. Ideally you want a Shower Pump Flange fitted in the top so the shower (see bottom of

this may not be necessary (I don't have one and it works fine). The cold water feed to the pump should be a separate pipe from the loft tank, taken lower down the tank than the feed into the bottom of the hot water cylinder. This is so if the tank in the loft empties for any reason, it's the hot water which stops (and the shower goes cold), rather than the cold water stopping first and the shower burning you.

If you look to price up an electric shower, don't forget to price up the cable. Often that costs more than the shower.

[Newshound]

+1. Be aware that the budget shower pumps as sold in sheds and Screwfix for ~£150 may only last a couple of years, but a Stuart Turner (over £300) will last forever.

[Man at B&Q]

Pump every time.

Ours has done 8 years so far. =A3100 "ShowerForce" I think.

We don't have a special flange, just tee'd off the usual hot water cylinder outlet.

MBQ

[The Natural Philosopher]

you have left out the infinitely better third option

Install a mains pressure hot water tank *anywhere it will fit* and preferably a water softener as well (replacing scaled up pressurised tanks is expensive).

Now all your water hot and cold - is at mains pressure, you no longer need to worry about it, and you no longer have to worry about freezing header tanks, sticking all valves and floods of water cascading down through the ceilings.

Most existing installations can be pretty quickly modified to work this way.

[Andrew Gabriel]

Mine's a NewTeam. I think it's original with the house (21 years). I looked at replacement cost a few years ago and it was £450, but they seem to have come down to around £300 now. (Fortunately, the problem turned out not to be the pump, which still works fine.)

[Man at B&Q]

What if two showers are in use at the same time? Do you only get half the flow to each?

We have one mixer plus pump and one integrated pump/mixer. Both can be used at the same time with no loss of performance (until the little darlings use up all the hot water).

MBQ

MBQ

[The Natural Philosopher]

no.

in practice - here at least - it is not possible to operate any of the showers flat out without flooding the house. So great is the flow rate, especially on 22mm pipework :-)

It certainly exceeds any pumped showers I have ever used.

The key things are to take a SUBSTANITAL - 22mm or so - feed from the mains stopcock to the tank and then feed all the other hot and cold from there.

If feeding two showers via one pipe, make that 22mm.

In practice you wont want to replumb everywhere, but its well worth making any new bits large bore.

IIRC I have 22mm everywhere except feeds to a single bathroom - those are 15mm except the master bathroom which has a tropical downpour rather than a shower.

As long as the sealed tank can be replenished via at least 22mm and the two showers are not on one long 15mm run, and the mains pressure is not pathetic, you will be fine.

Even if the above are all not met, you will still be better off than a header tank and a pump.

well yes. The rate at which they will use it up when its got the mains behind it is even worse. At least a 750 litre tank for a family..

[Brian Gaff]

Would you not need 2 pumps? The gravity feed of hot comes from the top of my tank, which I whought was normal. The other snag I have is that the cold is not from the mains, but from the tank that fills the hot tank.

Brian

[Brian Gaff]

Hang on a moment though. if we are just using hot water from a cylinder, its surely going to be smaller than the loft tank and will go cold long before it can exhaust the loft tank on the cold side. Brian

[Andy Burns]

Depends on how hot the tank stat is set for, and how hot a shower the O/P likes, I can certainly run out of cold before I run out of hot.

[Tim Lamb]

We have a Stuart Turner pump feeding an Aqualisa mixer shower from conventional tanks.

Initially we had air lock problems and the plumber fitted an Essex? flange.

Fine for most users but daughters...... its a power shower dad! Got to feel the water! So they empty the header tank and screw the temperature setting round full because the water runs cold. We have a huge header tank as well!

Shaving their legs is my current pet theory.

One day, when I have gathered the tuits, I will fit a second ball valve to the header.

regards

>

[Andy Champ]

Option 3: Tank fed shower with integral pump. Needs a low-power electric supply, and a feed of low-pressure hot and cold water.

These sort of things:

[Andrew Gabriel]

Due to some unforseen issue (e.g. ball valve stuck closed), the tank could be almost empty when you start your shower.

[Richard Russell]

Surely it's only better if the incoming water pressure is high enough? Ours rarely reaches as high as 3 bar, so our 'mains pressure' showers are by no means powerful.

Richard.

[Andrew Gabriel]

A shower pump is normally a pair of pumps attached to the same motor, although there are some single pump versions.

[John Rumm]

With a mixer shower you are usually using cold from the cistern for on side of the shower, and more cold from the cistern to replenish the hot cylinder. Combine this with a poor refill rate from a traditional ball valve, and you can quite easily run out of cold before hot.

[John Rumm]

Shower pumps normally have two impellers - often one one each end of the motor shaft - so they can pump hot and cold to keep the pressure balanced at the shower, but without mixing them in advance.

[The Natural Philosopher]

Deliberately flow restricted so the water comes out slightly more than warm.