There is a flow problem ie not enough water flowing,if water pressure is ok and the outlet hose and shower head are not kinked/blocked there is a filter on the inlet that could be blocked.If you have particularly high pressure the flow control valve could be faulty in which case it means a replacement "engine" as they call the shower interior
toptrish
February 2014
Automatic Answer
We may have found other answers which could help you.
howtomendit.com for free repair help, information and advice.
Try fixfault.com to fix plumbing.