Shower pump vs lifting hader tank for increased pressure

[gasket]

Hi folks,

Looking for some advice from those in the know.

I’m currently gutting a terrace house including a rewire and revisions to the plumbing.

The house has a recent condensing boiler which I would like to keep. It also has a standard thermostatic mixer shower.

I’ve bought a new mixing shower – a beautiful period style unit with a large, traditional rain head. I prefer this style and don’t want to fit an electric shower.

The output from the existing shower is OK, but I’d really like to increase the flow/pressure to make the most of the rain head on the new unit – an increase of 50%+ would be ideal.

The hot water system is gravity-fed, with a large header tank in the attic and the cold water feed to the shower is also gravity fed, with a smaller header tank in the attic. These tanks are currently around 1m above the shower head. The hot water cylinder is sitting at floor-level in the bathroom.

My plan all along has been to buy a pump to achieve the desired result, but a neighbour (retired plumber) has said the following:

“Pumps are a pain. In order to make the most of them you need to add additional outputs from the body of the hot water cylinder. You’d achieve the same result by lifting the header tanks in the loft – if you were to raise them another metre on a platform in the loft (2m drop rather than 1m drop) then you would double the pressure at the shower head”.

Is this right? I can’t argue with his logic, and lifting the tanks would not be a problem at all – there is plenty of space to build a strong platform. However it seems strange that such a simple fix could achieve the desired result.

I’m happy to draw a diagram if this would be helpful.

Really appreciate any help.

 

[muggles]

He's talking out of his arris. Even the most basic pump will have the same effect as lifting the tank ten metres, and installation time should be the same as lifting your tank up.

Buy a Stuart Turner Monsoon Twin Impeller

 

[bernardgreen]

Your neighbour is correct. Lifting the header tank will increase the pressure at the shower. Pumps work but are a real pain when they go wrong. or there is a power cut.

Simple is always best !

 

[flameport]

but a neighbour (retired plumber) has said the following:
“Pumps are a pain. In order to make the most of them you need to add additional outputs from the body of the hot water cylinder. You’d achieve the same result by lifting the header tanks in the loft – if you were to raise them another metre on a platform in the loft (2m drop rather than 1m drop) then you would double the pressure at the shower head”.

A separate cylinder outlet is the best arrangement, but not essential. Entirely possible to use the existing hot water outlet.
Unless you are replacing the cylinder anyway, little point in getting one with a separate side outlet.

Increasing the head from 1m to 2m will indeed double the pressure - the problem is that double almost nothing is still almost nothing.

A 2m head is equivalent to about 0.2 bar - barely enough to cause water to flow through most shower mixers. It will be totally useless with a large shower head.
This random example: http://www.screwfix.com/p/triton-levano-thermostatic-bar-diverter-mixer-shower-exposed-chrome/9369f
which has a moderately large head requires at least 0.5bar, and even at that pressure, the performance will be mediocre.