How to make the shower over my bath more powerful?

womble12345

I have a mixer tap on my bath with shower attachment but the shower is pretty weak. How can I make it more powerful?

I have a conventional boiler and a hot water tank. 

I did think it was the mixer at fault so I changed it for one of these a while ago https://www.screwfix.com/p/1-4-turn-dual-commercial-lever-bath-shower-mixer-bathroom-tap-chrome/25843 but that only made a minor difference. I have just measured how long it takes to fill a 1 litre jug and when using the taps (like you would to fill a bath) it fills the jug in 5 seconds (ie 12 litres per minute) but when using the shower head at a normal height it takes 25 seconds to fill the 1 litre jug (ie about 2.5 litres per minute). I assume the pressure is lost sending the water up the 1.3m shower hose. How can I boost this?

I have another shower in an en-suite that has a dedicated feed from the hot water tank and the cold water tank in the loft with a salamander twin shower pump and that is great and I was hoping to get something nearer to that. I recently measured how long the ensuite shower took to fill a 1 litre jug and it was 5 seconds so I make that 12 litres per minute. 

I did consider an electric shower but wouldnt this involve running a cable directly back to my fuse board? This would be very hard to route without hacking huge holes in walls, etc.

Another option is this pump fitted under the bath https://showerpowerbooster.co.uk/blog/fitting-a-pump-under-a-bath/. I could drill a hole in the wall under the bath and route the power cable to the room next door. Any thoughts on that?

Any other options?

benson1980

Aside from shower pumps as you say, another option would be unvented cylinder (assuming your system is gravity fed based on your description) so all hot water outlets would be pressurised. This would negate requirements for any pumps dependent upon your mains pressure being good, but obviously a lot more expensive (several thousand). There are other benefits- newer more efficient cylinder than you currently have I suspect, being able to get rid of the large cold water tank, sealed CH.

ThisIsWeird

Hi Womble.

That new mixer still requires a min 0.5 bar of pressure, which is quite high. Yes, it'll be the additional height of the hose that will be kaboshing your flow - in essence, the remaining 'head' of water (the distance between the shower head and the cold water tank) will have been reduced, coupled with a bit of added friction in the hose itself.

Mira make a mixer that seemingly can operate well on only 0.1bar, but they ain't cheap, and won't guarantee the improvement you want. So, solutions are:

Raise the height of the CWS in the loft if you can.

Redo the pipework betwixt the CWS and hot cylinder and the mixer to be more direct, always have a drop, have slow bends, and possibly even in 1" pipe (tho' shouldn't be necessary).

Change to unvented as Benson says - expensive option, and also relies on the mains pressure being good.

Fit any manner of pumps. You know that these work as you already have one! An alternative, tho', might be a wall-mounted booster shower as made by Triton, I think? It looks like an electric shower, but has a small, low voltage pump inside it. You can check the specs to ensure it'll do what you want, but I understand they are pretty nifty. Yes, it'll need a power supply, but only a 'normal' one from a nearby cable - easy if it's in the loft. The actual shower is, I understand, supplied via a PSU so only has ELV going to it, so very safe and DIYable.

womble12345

Thanks ThisIsWeird. You have given me a few things to ponder.

What do you mean by CWS? Do you mean the big cold water tank in my loft? I think raising that will be too much work I am afraid.

I am assuming by the Triton booster shower you mean this?
https://www.tritonshowers.co.uk/t40i-booster-pump
That does sound pretty similar to https://showerpowerbooster.co.uk/blog/fitting-a-pump-under-a-bath/ except that one is hidden away under the bath.

The unvented cylinder option sounds too expensive I am afraid.

ThisIsWeird

womble12345 said:

Thanks ThisIsWeird. You have given me a few things to ponder.

What do you mean by CWS? Do you mean the big cold water tank in my loft? I think raising that will be too much work I am afraid.

I am assuming by the Triton booster shower you mean this?
https://www.tritonshowers.co.uk/t40i-booster-pump
That does sound pretty similar to https://showerpowerbooster.co.uk/blog/fitting-a-pump-under-a-bath/ except that one is hidden away under the bath.

The unvented cylinder option sounds too expensive I am afraid.

Yes, the Cold Water Storage tank. It's not 'difficult' to move, but it would have to be worth it - say to gain at least a further 500mm height, coupled with a more direct - perhaps dedicated - pipe run to your bathroom. And a lower-pressure deck mixer...

Yes, that Triton is what I was thinking of. And, yes, not a dissimilar idea to adding a shower pump - it uses an internal pump, and won't be as powerful. Looks like it's not available any more?!

The low-pressure Mira deck mixer I was thinking of also doesn't appear to be available any more! It was a huge 'hotel'-looking, back/shower mixer, and was also pretty expensive, tho' I managed to pick one up for only £75 a few years back for my bro. It's certainly quality, and does the job well.

Hard to actually suggest what to go for. A 'pump' will work, little question. Other solutions - relying on increasing the 'head' and/or reducing the flow resistance in the mixer - are relative unknowns, so would be a gamble. I mean they are bound to help, possibly quite significantly, but it all depends on how much improvement you actually want.

knightstyle

The simplest cheapest way to increase pressure is to raise the cold water tank in the loft to as high as possible.  

Apodemus

ThisIsWeird said:

womble12345 said:

Thanks ThisIsWeird. You have given me a few things to ponder.

What do you mean by CWS? Do you mean the big cold water tank in my loft? I think raising that will be too much work I am afraid.

I am assuming by the Triton booster shower you mean this?
https://www.tritonshowers.co.uk/t40i-booster-pump
That does sound pretty similar to https://showerpowerbooster.co.uk/blog/fitting-a-pump-under-a-bath/ except that one is hidden away under the bath.

The unvented cylinder option sounds too expensive I am afraid.

Yes, that Triton is what I was thinking of. And, yes, not a dissimilar idea to adding a shower pump - it uses an internal pump, and won't be as powerful. Looks like it's not available any more?!

Interesting bit of kit...but...
Easy to install with no plumbing connections required.How on earth can you have a shower with no plumbing connections?  Perhaps that's why its no longer available! 

womble12345

Thanks for all the tips.

On a related note I did change the float valve in the CWS last week and in doing so I thought it may be a good idea to bend the arm of it down a bit which has dropped the water level by about 100mm. I have had poor pressure for years though so this isnt the cause but it cannot help so I shall be bending the arm straight again ASAP!

ThisIsWeird

womble12345 said:

Thanks for all the tips.

On a related note I did change the float valve in the CWS last week and in doing so I thought it may be a good idea to bend the arm of it down a bit which has dropped the water level by about 100mm. I have had poor pressure for years though so this isnt the cause but it cannot help so I shall be bending the arm straight again ASAP!

A good move in terms of being extra 'safe', but it won't have helped the pressure. Having said that, the 100mm difference would be very minor, possibly not noticeable. 

Looking at the CWS, how far up could it be lifted? How much Headroom' does it have? And is the pipework tortuous or quite well laid out? Does it go UP at any point, even slightly? Direct pipe route to the bathroom?

womble12345

I reckon the CWS could be lifted about 500mm but not much more as the roof narrows towards the top. The pipework is quite well laid out. It is a standard 2 storey house, the CWS is in the loft. There is no direct pipe to the bathroom, it goes down to the airing cupboard and then under the floorboards across the hall and under the bath, so yes it does go UP from the floor to the bath.

I am thinking that the inline pumps under the bath is my best option, it would cost about £200 and is DIYable as I can power it from a socket in the wall behind the bath.  It is also the least upheaval and the highest chance of improving pressure.

ThisIsWeird

womble12345 said:

I reckon the CWS could be lifted about 500mm but not much more as the roof narrows towards the top. The pipework is quite well laid out. It is a standard 2 storey house, the CWS is in the loft. There is no direct pipe to the bathroom, it goes down to the airing cupboard and then under the floorboards across the hall and under the bath, so yes it does go UP from the floor to the bath.

I am thinking that the inline pumps under the bath is my best option, it would cost about £200 and is DIYable as I can power it from a socket in the wall behind the bath.  It is also the least upheaval and the highest chance of improving pressure.

I think you are right - it's doable, affordable, and will have guaranteed results.

Do you know what a Surrey flange is? (other home-counties are also available...) I wonder if your hot cylinder already has one, since you have another pumped shower? If not, then you may need one, but I'd happily try it without first.

The hot cylinder outputs its hot supply from the very top-centre of the tank. This pipe soon tees, with a side pipe taking the hot water to your taps, and the usually-vertical pipe heading up as an 'expansion' to the CWS in t'loft. When you open a hot tap, it's the pressure from the stored cold water coming in near the bottom of the hot tank that pushes the hot water out t'top, yes? Now, when you add a pump to the hot pipe, you are now 'sucking' the hot water out, and the cold might struggle to refill it quickly enough. What will happen to some degree is that the column of water normally sitting in that vertical expansion pipe will also be sucked downwards towards the cylinder. If that column is pulled down as far as the 'tee', then air will be drawn into that hot pipe = splutters.

A Surrey flange sits in the cylinder top, and sends a short take-up pipe further down into the hot tank, and the pump will be sucking from inside there instead! Quite easy to fit if needed, but try it without first.