Shower water pressure

[Lindnarden]

*Steps carefully into forum with dictionary and thesaurus primed*

Hi,

Our en suite bathromm is finally finished but the water pressure out of the (admittedly large) shower head is somewhat disappointing. Pressure coming into the house is, I think, 3 bar (does that sound right ?) and I have had one plumber say that the pipework taking the hot and cold water feed upstairs is too narrow thus causing the problem.

Does this a) sound like a likely explanation and b) can the problem be ameliorated (*packs away well thumbed thesaurus*) with some kind of pump gubbins - I have tried to persuade the good lady wife that the current setup is akin to a tropical rain forest shower but sadly she hails from a land where the water from shower heads can effectively be used for trepanning.

Thank you all for your kind indulgence.

[Dick Smith]

When we had similar it was a crimped pipe, so it may be worth checking for that before you commit to any significant expense.

[Deimos]

3 bar sounds right to me. at least it is what my plumber said. When I purchased the house there was no pressure regulator which he commented don and I asked him to fit one (he said 3 bars).

I actually believe it is worthwhile as this plumber tends to avoid all possible new work (as he already has far more than he can do so tends not to propose anything not 110% necessary).

Ian

[Lindnarden]

I don't think it's a crimped pipe because we had the same issue before doing this bathroom - turning on any cold tap downstairs reduced the old shower (in a different bathroom) to a trickle - the pressure out of the outside tap is good enough to clean dried paint off a plastic paint tray

[Dick Smith]

Pity. We have a pumped shower in the UK and it is a bit noisy, but otherwise trouble free. Fix it on a rubber mat to cut down the noise.

[Lindnarden]

Does the pump have to be in the same room - the hot and cold pipes are accessible from the utility room downstairs - forgive my ignorance but presumably it attaches to them somehow [8-)]

[Dick Smith]

Ours is in the cupboard next to the bath, but I imagine it could be anywhere. It is controlled by the shower unit being turned on (that's the limit of my technical knowledge!) so I can't see why not. It's very small and compact.

The utility might make it easier to control the noise.

[Lindnarden]

I assume then, that if it is attached to the hot and cold feeds before they hit the upstairs floors it will pump water to all the baths and showers upstairs......which would be nice.

I guess the next question is roughly how much would I be looking at for parts and fitting....and how long would it take - it doesn't sound like something that should decomission the house water supply for days on end.

[Dick Smith]

You've got me there - ours was part of a bathroom refurb. and just feeds the shower.

There must be a plumber in France reading this who can help, surely?

[Babbles]

We've had some of those really large shower heads in the new bathrooms, don't expect them to be like power showers more like rain, they use a lot less water get you really wet so are better for the enviroment , but if it is just a trickle there probably is something not quite right, are they heated via a combi boiler or a hot water tank as if the latter the pressure is greater.[:)]

[Lindnarden]

The hot water comes out of a massive Wiesmann boiler not a combi.....my other concern is that, as we don't have a  cold water tank, how do we fit a pump as elsewhere on the interweb I have read that the cold water bit (sic) of the pump shoul NOT be connected direct to the mains....

[tj]

[quote user="Lindnarden"]
 and I have had one plumber say that the pipework taking the hot and cold water feed upstairs is too narrow thus causing the problem.

[/quote]

the pipe should be a minimum of 16 mm anything less would explain the problem,

[Rodie]

you cant really fit a pump on the main ,maybe the showerhead is restrictive or there is debis in the shower valve even if it is new

[Dave&Olive]

[quote user="tj"]

[quote user="Lindnarden"]
 and I have had one plumber say that the pipework taking the hot and cold water feed upstairs is too narrow thus causing the problem.

[/quote]

the pipe should be a minimum of 16 mm anything less would explain the problem,

[/quote]

 hi ok

              that man just gave the answer . it`s  a volume not  a pressure problem . 3 bar is enough  , but 16mm pipe will give you at least 4 x`s the amount of water than  a 12 mm pipe  

   dave

[Gyn_Paul]

So. What size pipes do you have feeding the shower, and how far is it from the hot water cylinder?

[Lindnarden]

The pipes look small (an expert speaks) - I would say 14mm at most. The shower, as the crow flys is about 10 feet above the hot water tank but probably triple that in pipe terms.

I'm guessing the options are the pump route - with the not being able to attach it to the mains caveat.....or replace all the thin pipework with something a little more robust.

[Pierre ZFP]

Before you do all that, have a look at the penultimate (pause to put away theasaurus)  link in the chain. My shower problems were all due to the flexible hose from the shower cubicle to the actual head being a cheap nasty one (well actually not that cheap) and a very small bore. Disconnected it at cubicle end and there was lots of water, put it back and undid the shower head and the flow from the flexible tube was much reduced.  New hose for a few quid from UK Home Base solved everything

[Lindnarden]

Sadly a flusing of the loo means that the sink taps reduce to a mere dribble so I don't think its the shower hose - however I'm not an expert

[Pierre ZFP]

Hmmm, well a tip I was shown by a plumber was to to turn on a cold tap at a rate that it would fill a pint (call it half a litre) glass in about 10 seconds or less.  Keep it running for a minute or more and see if the flow is about the same.  A significant reduction was an indication of furred up pipes - sorry, tubes (got into trouble for 'pipes' before).  3 Bar pressure should be more than enough for a household with everything going at the same time.  Last time I looked I had between 1 and 1.5 bar (I have a gauge on my boiler - that's the water heater, not the OH) and it was plenty

[Anton Redman]

If it is 14mm at the outside then it is to small for a shower. If the pipers are cast irn they may well be furred as well.  I am pretty sure a power shower will not cure 14 mm pipes. Large header tank in loft, sourcing a Hot Water cylinder with at least 22 mm outlet then the power shower with hot water  - your French plumber will think you have gone mad.

If you have an outside garden tap which does not go through the 14 mm upstairs plumbing check the flow through the shower head using cold only with the hot inlet blanked off. If the flow through that is sufficient then ten feet lift through decent sized pipes will have no impact.

[Gyn_Paul]

It may be that the feed to the hot cylinder, and the continuation therefrom to the shower are too long and too small bore.

Fitting a pump (which you could only do to the hot feed anyway) would

probably not help you that much. A power shower pump needs to work on

both H & C feeds in order to balance the flow, so getting a

comfortable, stable mix would alway be a problem. Also, I wonder if it

would manage to achieve much of an improvement anyway. As far as I'm

aware power shower pumps are good at boosting a flow (pushing the water

through pipes where there is no appreciable resistance in the flow coming to

the pump:  the typical situation would be a bathroom fed by 22mm

pipes where the header tank is in the loft (2 metres or so above the

shower head). The flow is piss-poor because head is so low, but the

bore of the pipes is so large that the potential flow is huge.

Here a pump works well. I suspect your system displays almost the

reverse symptoms: a good static head (i.e. if you put a pressure metre

on the closed hot or cold supply it would show 3 bar, but once you open

the tap, the pressure drops to almost nothing because the demand far

outstrips the supply; the flow is being clogged by the small bore of

the pipes.

Bigger pipes - that's the answer

And speaking of small bores, that's quite enough from me !

p

[Nick Trollope]

Doesn't this go back to good ol' Boyles Law - PV=K? Given that you can't compress water, then the volume  of the water in a pipe (and hence out of the shower head) will always remain the same, regardless of how hard you push it?

If you are interested, P is pressure V is volume and K is a constant. Boyle's law actually applies to gasses, but I think that liquids & gasses perform much the same.....

This is O level physics stuff isn't it Dick?

 

[powerdesal]

I rather think that Bernoulli is more relevant than Boyle in this case.

[bejay]

[quote user="powerdesal"]I rather think that Bernoulli is more relevant than Boyle in this case.
[/quote]

Or even Ohms law.

bj

[Nick Trollope]

[quote user="bejay"]

[quote user="powerdesal"]I rather think that Bernoulli is more relevant than Boyle in this case.
[/quote]

Or even Ohms law.

bj

[/quote]

Bernoulli is certainly relevent to Ohm's law, but I am not convinced that it is to th OP's problem. How so, Steve?