Shower pump under the bath and a rigid riser to the head

by **missionary** » Thu Apr 02, 2009 8:54 am

I want to install a new bath with shower mixer supplied by a twin impeller pump located underneath. This to replace a wall mounted power shower fed down from the ceiling. The existing shower is not fed from a Surrey flange, so would the new pump need one? - so far there is no noise/bubbling/spluttering from the old system.

Second, we are happy to have a shower running from a bath filler/mixer tap, but would like a rigid riser to the shower head. I have seen one on a TV programme once but cannot find any in catalogues or web sites. Can anyone point me to such a thing please?

Third, some may ask why not fit a concealed shower mixer? Well, yes I could, but it will need excavating the stud wall to which I want to fit the shower. If I have to go that route it would mean removing a section of plasterboard from the reverse side of the stud wall, accessible, but is it really worth it? I really don't think so. But do any of you have a better idea? Help will be much appreciated, thanks

Mish

by **stoneyboy** » Thu Apr 02, 2009 8:48 pm

missionary,
Try the shower pump without a flange and see if it works OK.
I've never seen a rigid riser fed by a bath filler/mixer tap fitted to the edge of a bath they are generally fitted direct into the shower valve. Most manufacturers produce a rigid riser with fixed shower head.
end

by **plumbbob** » Thu Apr 02, 2009 8:53 pm

Not straight forward!

You can't connect pump under the bath to to the tap feed. The cold is at high pressure? so would damage the pump and the hot would suck air in from various places. Look at the installation instructions that come with any shower or pump for advice on how it can be fitted.

You don't always need a Surrey flange. It all depends on other factors.

Fitting a mixer to an existing stud wall is not difficult. I do it regularly. There is no need to chop big holes in the wall. Exactly what type of construction is it?

by **missionary** » Fri Apr 03, 2009 8:35 am

Thanks gents.

Perhaps I should have said that the cold supply is not from the rising main but from the header tank. Sorry.

The wall is in a 1980 house so is the usual plasterboard on wooden studs. The back face of the wall is onto the landing so plenty of access all round. As I am installing new bath, loo with concealed cistern, basin vanity unit, ply floor and tiles. I have plenty of scope to make the fittings 'right'.

Comment on shower riser noted, this is the problem when you see these things on TV ! We even went to posh plumber Porcellanosa in Watford hoping to find one but they had nothing like it. But its not a major factor for us. Though I would welcome recommendations for a good catalogue/website for showers. HTH

Thanks again

mish

by **plumbbob** » Sat Apr 04, 2009 5:41 pm

A shower needs separate supplies (except mains pressure systems) to work reliably. A shower pump must be near the cylinder and header tank and pump the water to the shower. After all, pumps, well, pump not suck.

If you want a top range shower start with Grohe or Bristan. Top mid range is Mira folowed by Triton.

Find the top of the stud wall in the loft. To gain access to the cavity, cut a 1" hole for each pipe. If you are lucky, you should be able to drop a pipe down the cavity for each side of the feed. Cut holes in the bathroom wall to gain access to the pipes and fit elbows so as the pipes will protrude from the wall.

by **missionary** » Fri Apr 17, 2009 9:18 am

Thanks PB.

Apologies for delayed reply but I have to work outside the country on short notice at times.

The pump will certainly be below the tanks even if I have to revert to mounting it in the airing cupboard - which I want to avoid. I fit marine pumps in my other life so am used to their requirements and the physics involved.

As for mounting on the wall, there is no problem dropping a pipe down from the loft but its just that some of the shower fittings I have contemplated fitting one that has a large mounting plate that goes in the cavity and the studs fall in the wrong place. But there again I will just have to change the fitting won't I !

I have to go away again now, but will be back on the case later in May and will surely be back here. Again thanks to all for your kind help.

Mish

by **plumbbob** » Fri Apr 17, 2009 9:30 pm

"one that has a large mounting plate that goes in the cavity" What make had you in mind then?

Generally, it is not the studs that are the problem, but rather the short noggins that fit horizontally blocking the cavity.

If you don't want to disturb the bathroom wall, it is possible to cut holes in the other side of the wall and work from there. If the holes are cut carefully, it is possible to repair the wall easily with minimal re-decoration necessary.