Best way to increase water pressure to a shower

[Lusi83]

This is for my non internet savvy dad - so if you need more details it may take a little while to find out.

Basically system they have is 35 yrs old - header tank in loft and a hot water cylinder in an airing cupboard. Had a new boiler a couple of years ago but was connected to old cylinder/tank and both are coming to the end of their life and need replacing. He definitely wants to stick with a hot water cylinder.
The water pressure on the shower over bath has always been a bit pathetic so looking at a way to improve it at the same time. The mains water pressure is quite good (haven't got a bar/ or litre/min figure - measuring complicated by the water use reducers on mains feed taps) but the feed upstairs is only 15mm and would be a real pain to change to 22mm (2 ft thick solid stone walls, a later extension, L shaped house etc). And the main feed pipe to house is 20 m long lead pipe -probably not that big anyway.

Bathroom sink is fed by cold water mains.
Bath/Shower cold is fed from the header tank and the header tank fills the cylinder.

So he thinks he has 3 options
1. an unvented tank and a direct cold feed.
2. current cylinder/header tank set up and a pump
3. Keep current system (new cylinder/tank!) but raise the height of the header tank in loft - currently there is about 3 ft height difference between the header tank and the shower head. Tank could be moved to the gable and raised by another 3-4 ft -if not more.

So he has had a couple of plumbers to quote...
They both have said the pump approach is maybe not the best - potentially empty the tanks before they've filled....plus maintenance /replacement/failure

One thinks the unvented tank is the way to go - the other says that the pressure can only be as good as the 15 mm feed will allow so not ideal and does away with one advantage of having a tank - you have some water even if it is cut off for some reason.
He recommended raising the header tank.

Anyone have any thoughts? I thought (apart from yearly maintenance) an unvented tank would be the way to go - but now having my doubts

 

[Dan Robinson]

Don't confuse pressure and flow.

What is the mains pressure?


If upgrading the water main isn't feasible then an unvented cylinder and accumulator

 

[Lusi83]

Thanks...
Don't have a figure for the pressure but it is 'good' ...or at least they get a decent flow rate out of the taps ...thought the flow gave an indication of the pressure - can't get a good flow rate without decent pressure???? But I do get confused - will have to get my head round it -but we need a decent flow rate

Had never heard of an accumulator tank ...just looked it up - it would be replace the header tank could also go in the attic too ...that is a possibility I guess ...I'll have to read up a bit about it ...

 

[Burnerman]

Would a 'Power Shower' be of any interest to you?
They look like a traditional electric shower (i.e a box on the wall) but they can be fed with 15mm gravity supplies. They have an internal pump to boost the flow and I feel they are an excellent and cheap way to boost a poor shower. They need an electrical supply of course, but not a high current one.
The last one I fitted was a Mira Excell I think....its been used every day and 7 years later, still delivering.
John

 

[kittedup]

20 litre bucket of water on your head = good flow rate, low pressure
20 litre of water squirted from syringe = poor flow rate, high pressure

 

[Lusi83]

Not sure about the Power shower - will talk to him about it ...
But guess that might disrupt the bathroom more than he wants to - tiles are pretty good, not too dated - wouldn't want to mess with the walls and the shower end is an outside wall (the 2ft thick stone) so can't get in from the back...

And kittedup - thanks for that ...it does help ...but still get confused!
(I can get my head round it - then I think - We have too high mains pressure ...have to keep it turned down at the stop cock. Have an Ikea kitchen tap with tiny tails? (feeds) - Tap full on and it seems like it will make a hole in the bottom of the sink - but try and fill a pan and it takes forever ...so that's high pressure /low flow rate ... giving an impression of a high flow rate...
I guess for a good shower you need reasonable pressure and a good flow rate ...at the moment you get wetter quicker standing out in the rain!

 

[longdogs]

Your cold water (at the kitchen sink) comes from the mains so will be high pressure but your hot water comes from the tank via the cylinder so will be low pressure.

If, you say, your dad is insisting on keeping the current set up then you are looking at replacing the cylinder and replacing the tank? then you still have the problem with the shower. As Dan suggested, an unvented cylinder would replace the items and sort out your shower as well.

 

[Dan Robinson]

I posted a video of the effectiveness of an accumulator not long ago. On my mobile at the moment so can't post links direct from you tube.

 

[Dan Robinson]

This is being run from a 15mm water main at 3 bar.


http://youtu.be/6iiA3qgN3Lw

 

[roguetrader]

Why not stick to the system he has and fit an electric shower off the 15mm rising main?
Least upheaval for your dad, less stress on an old system and its tried and trusted.

 

[Lusi83]

Thanks - I've got a problem with my internet connection at the moment and can't watch videos until its sorted (its really slow...reminds me of dial up! and it keeps stopping and starting- driving me insane) -but I will when I can...
Like I said for an electric shower isn't he is going to have to run the cables/pipes through the tiled wall? ...which he won't be keen on...
If he keeps his current set up he will raise the header tank ...so that will increase the pressure - which (unless I'm wrong) will in theory do the same as an accumulator tank -except that I suspect the accumulator may be more effective...
Still trying to find out more about them ...typical internet problems just after posting a question!

 

[JohnD]

you have to raise the tank by a lot to get significant increase in pressure. I have a bathroom where the shower head is about four metres below the tank, which gives a better flow than most UK tank showers, and is "weak but adequate" and one shower that is 10metres below the tank, which gives 1bar pressure, and a "quite good" shower, by UK standards, but it is nowhere near as good as an unvented cylinder can give.

An electric shower can have quite good pressure but the amount of hot water it delivers is very poor.