Power Shower Problems

[robroy]

Hot water is via a hot water tank which is upstairs this is fed from a tank in the loft, water is heated by a gas boiler.
Generally the hot water pressure from all taps in the house is poor, cold water pressure is fine
If I run the shower it starts ok then after a minute or so the pressure suddenly drops and the noise from the shower pump increases, temperature of water from the shower is not affected.
The hot water cylinder is not on the floor of the airing cupboard but set quite high up as it is above the stairs, the top of the tank is only about 2 foot below the ceiling. The hot water feed for the shower looks to be an after thought, the 22mm copper pipe coming from the top of the tank has had a plastic push fit 22mm T connection fitted reducing down to 15mm. 15mm plastic piping then "curves" up through the ceiling into the loft then back down again to feed the shower.
The house is only 6 years old and I would guess the shower was put in later.
Any advice as to what the problem with the shower is will be appreciated

 

[gas4you]

Sounds as though the hot take off to the shower is incorrect. You should have an essex or surrey flange supplying the hot water outlet indepentently.

Your set up sounds as if it is sucking air down the vent which would explain the hot water stopping so quick and the noisey pump.

The cold feed to the power shower should also be independant, direct fron the cold storage tank in loft.

Do a serach for essex or surrey flange.