Shower flow and temperature problem

[giraffe]

I have a Newteam 201 powershower which has a motorized pump located in the shower casing.

It is mixer shower that is fed by a hot and cold pipe. The hot water seems to be coming out of the hot water cylinder in the airing cupboard.

The problem is that the shower works great for about 5-10 mins but then suddenly makes groaning noises and the flow falls away dramatically and the temperature gets hotter. This is when the power for the motor is switched on. When it is switched off the flow reduces but the temperature stays even for longer.

Could anyone someone give me an clue before I take the thing off the wall and look into it with a stupid clueless look on my face?

Thanks for the opinions

Giraffe

 

[corgiman]

Sounds like its pulling air for somewhere

does it have seperate hot and cold feeds to it from the cylinder and cold water cistern

if not you going to have to provide them, this info should be on the manufacturers instructions