Isolating electric shower

[WHONOES]

Have a pump fitted between the hot tank and the shower also the incoming cold supply for the shower as well. Works perfectly. And I live on a hill.

 

[Bluejets]

AS Alec-t says, you have a flow problem which was why I originally said get some new pipes.

If you have sufficient pressure for the shower alone, and then it drops when another tap turns on, that's a flow problem, not pressure.

Any amount of pumps is not going to cure that.

Which means the pipes are too small to begin with or if they are gal pipes or whatever, probably rusted up internally over the years.

 

[duke37]

There is obviously a flow problem so that the shower and a running tap can not be adequately supplied simultaneously..
I suggested a pump to supply the shower which will starve the running tap of its supply and give priority to the shower.