My new shower has very little water flow. It has been installed by a plumber / bathroom fitters. We have a boiler (not combi) and the shower works off the hot water system and a mixer valve. The previous shower was the same general system but had a decent flow. You can't have a good shower with the new one due to the poor flow. Are there flow restrictors fitted in new showers? Can any one suggest a remedy /explanation for the poor flow with our new shower. The old one was ok for 20yrs . Why should the new one be so bad?