Hello, here's a problem that I don't think I'm the first person to have on here. I have a TRevi Boost shower installed on a combi boiler system. The temperature keeps fluctuating from lukewarm to mildly warm, nowhere near as hot as hot water out of a tap. On the advice of Trevi themselves I've removed the thermostatic control valve (Boost Valve) and given it a good clean out (not that there seemed to be much wrong with it in the first place, but it doesn't seem any better. Can anybody offer advice please? Thanks