Power shower Problem - No hot water..

[mattman]

Just installed a power shower tower today - it has been used previously but i was told it was working fine when removed.
after spending ages getting power through to the shower, replacing leaking pipes etc I got the thing all fired up.
Heres the problem - you can hear the pump working fine, and on full cold it seems to work OK, however when you crank it over to hot all I get is a dribble of water coming out. Short of taking it all apart again and throwing it away - any ideas I can try or is it a plumber job?

[Ferg]

Air lock? Do you have pipework that goes up and then down again?

[tr7v8]

As Ferg said, they are a centrifugal pump so don't self prime. Also they have filters in each feed, ours occasionally picks up gunge from the cold tank into the hot & that causes grief.
Finally is the hot water temp high enough. The cold has been so cold this winter I've had to jack the hot temp up at the tank thermostat because otherwise it ran out of hot volume.

[mattman]

Thanks for the replies guys - I found the problem - the flexible pipes I used to connect to the copper pipe in the wall weren't quite as flexible as I expected, so when the shower was tightened aganist the wall it was kinking the pipe and restricting the water flow. So tomorrow I'll have to take it apart again and modify the connection to give it a bit more flex.