low pressure at new shower head

[cherian]

the new shower fitted in my friends extension has very little pressure...unusable ...but within spec according to the plumber who fit it.
the bath and sink in the same room are ok ...it is a gravity fed system

i think the plumber has done something wrong but dont know what ...any help!!!!

 

[seco services]

hows it plumbed in ?
what shower is it ?

 

[mogget]

the new shower fitted in my friends extension has very little pressure...unusable ...but within spec according to the plumber who fit it.
the bath and sink in the same room are ok ...it is a gravity fed system

i think the plumber has done something wrong but dont know what ...any help!!!!

Some cheaper shower hoses have a small bore (~7mm) and will cause problems with tank fed supplies.

There are high pressure and low pressure shower heads, you need the right one.

Some shower valves (particularly thermostatic 'bar' mixers) are suitable for high pressure only and will not work when supplied from a tank unless a booster pump is fitted.

If you unscrew the hose from the valve and turn on the water, this should help you find out where the flow is restricted. If there's a poor flow with the hose and showerhead removed, the fault is with the valve or the pipework supplying it.

 

[cherian]

there is a thermostatic bar on the system but the manufacturers say it is suitable for low pressure...is only letting 1.5 litres a minute through even though ensuite is at 8 litres a minute...shower head checked and no change....

 

[mogget]

there is a thermostatic bar on the system but the manufacturers say it is suitable for low pressure...is only letting 1.5 litres a minute through even though ensuite is at 8 litres a minute...shower head checked and no change....

What is the approximate vertical distance between the shower head and the base of the cold water storage cistern in the attic?

 

[cherian]

distant would be about 6 feet approx

 

[mogget]

If the shower is fed via 15mm pipe branched from elsewhere in the ensuite this could easily explain the problem. Ideally the shower should have its own feeds in 22mm from the cylinder and cold water cistern. Even then it will likely only give a moderate drenching due to only having six or seven feet of working head.

If you want 'power shower' performance you'd need to consider either a shower pump or possibly an electric shower, short of converting to mains pressure hot water.

It may be worth looking again at the manufacturer's specification for the shower valve. You'll have about 0.2bar static pressure but if the pipework is undersized the working pressure will be considerably less.

 

[cherian]

thanks for help ...it appears that the shower must not have its own feed , by the way the plumber seems to have walked away from the problem..
the builders have tiled over all the pipework ( boxed in) so my friend is reluctant to strip this all off as cost would be prohibitive. i will check the valve specs again to see if replacing this would solve the problem...this new shower is in the bathroom and like i say she has also a shower in a seperate ensuite that works so i am guessing that the pressure is ok in the system...

 

[cherian]

Back again...
I have read the mixer tap specs and thought the plumber might not have removed the flow restrictors but he has.....

the sink in the bathroom has good cold pressure, but the bath and the shower have poor pressure...so i am thinking there is some link between the two...