shower pressure/flow

[graham]

I see that the question of shower flow rates hasn't been raised in, oh, hours, so to fill this gap....

Help! My shower flow is rubbish!

I'm not after spine tinging power shower performance, just enough flow to wash the soap out of my hair..

I've measured various flow rates, and my question is whether there is anything out of the ordinary with these figures given the setup? And if not can I 'fine tune' the flow up to acceptable in any way, or should I give up and buy a pump?

The setup is: Cold supply: 15mm pipe from cold tank to shower; total run of ~5m, with

2 gentle 90 degree bends, 2 90 degree elbows, and a 45 degree elbow. btw, the take off from the cwt is level with the take off to the hot tank (tut tut?). Hot supply: 15mm pipe taken from the 22m hot "down service" supply pipe taken off just below the up-to-overflow-into-the-cold-tank T (ie. the 22mm has already done a gentle 90 degree bend plus 2 Tees); total run of 15mm pipe is ~3m with 1 gentle 90 degree, 2 90 degree elbows, and a 45 degree elbow.

Flow rate out of shower valve (~2m below bottom of CWT) is 14 l/min.

Adding the shower hose reduces flow to 8.5 l/min (level with the shower valve). Shower hose internal bore is around 12mm.

Adding the shower head reduces flow to 7.5 l/min (again level with shower valve). This would be ok, but the final straw is...

Raising the shower head 0.8m so I can stand under it reduces flow to 4.5 l/min. ARGH!

Assuming those figures are par for the course, sniff, then a google of the archive suggests my options are...

1 - improve flow, ie. fit 22mm pipe, and take the hot supply direct from the tank (surrey flange). Can anyone quantify how much difference these are likely to make? My guess is not very much, but then I'm working on marginal amounts here anyway...

2 - improve pressure, ie.

2.1 - fit a pump 2.2 raise the height of the CWT.

The maximum the CWT can be raised is ~60cm - lowering the handset by this suggests a flow of 6 l/min, not enough on its own, and a heap of effort.

I'm reluctant to go the pump route due to likely noise, and it's overkill in that it'll deliver more water than is needed. It may require

22mm piping too (and definitely the surrey flange).

In summary, I'd like to avoid a pump, but am I stuffed?

rgds all, graham.

[ALex]

you need at least a 1 m head from shower head to base of cold watertank,this gives a very good shower,you will also be best advised to have a seperate cold supply from tank to shower outlet,the only other route is mains electric,or power shower

[John Rumm]

Its the distance to the top of the water in the tank that counts (assuming the cold main can refill it fast enough)

That is the killer - you are probably only leaving 4' of head.

With the existing valve - probably not much.

You can get some shower valves that have 22mm inlets and are designed for low pressure operation (I have fitted a Trevi one like this once - similar head to your situation, and it was not exciting, but certainly acceptable)

Just changing the shower head for one with less flow resistance may help.

2.3 if you have cold mains nearby use a venturi shower

Not necessarily...

I did one for SWMBO's aunt a while back where she had a similar setup, and wanted an improvement in the shower, but did not seek the being flayed alive sort of shower experience. I fitted a Stuart Turner 1.4 bar pump and it perked it up nicely. Not being hugely powerful also meant that it ran fine from the normal hot water outlet of the tank without need to fit a Surrey flange (I was anticipating needing to make one up, but in the end there was no need). It had 15mm connections (although I piped some of it in 22mm since the same pipes also ran on to the bath). Sat on a rubber mount with some wooden boxing over in the airing cupboard you could not really hear it over the shower anyway.

There are other options, but don't dismiss a pump out of hand.

[manatbandq]

That matches my experience. Once I'm in the shower I can't hear the pump and the noise escaping from the airing cupboard doesn't wake anyone.

MBQ

[graham]

Thanks for the comments guys. I'll probably go the pump route, so a couple of follow-up questions:

noise - John, you mention "some wooden boxing over" - is there not an issue with the pump getting too hot?

plumbing - plastic pipe might be quicker to plumb though they probably entail pipe inserts which could impede flow. Any comments?

wiring - is a spur off the RCD protected mains ring acceptable (along with fused isolating switch), or does it need its own feed from the consumer unit?

makes - stuart turner & watermill seem to do similarly spec'd products - are these both reasonable (I'm thinking the "cheap" end of the ranges (eg.

or again g.

[Andy Hall]

Have a look at the Stuart Turner Monsoon 1.8bar product. There is a version of this in a padded package which reduces noise a great deal

Try using 22mm if the runs are long.

Yes that's fine subject to the switch not being in an unacceptable zone of a bathroom.

and reliable and they have excellent spares and service backups. Components like seals etc. which tend to be required eventually can be obtained as part of a service kit for about £10.

Watermill is less well known in this market space but are now owned by Grundfos who have a good reputation.

I'd still choose Stuart Turner.

[John Rumm]

This was mainly for aesthetics, and to stop the pump getting smothered in clothes in the airing cupboard. So the box had a top, left and front. The right being the wall beside, and the back was open. It was also generously sized to accommodate the loop over of the pipes above the pump and its flexy tails. So no danger of it getting too hot. (they are also water cooled!)

The size of the restriction is only a part of the equation, the length of it counts as well. So a couple of inserts will make very little difference. The pump also has push fit fittings, so can take plastic pipe directly.

No, a fused spur is fine (total load is only a few hundred watt).

Stuart turner would get my vote.

Yup, that was what I used.