I have recently had one of those new type power showers with a thermostat installed this summer. The shower heats up via the combi-boiler. The shower was working perfectly until about a month ago where the shower has recently been running at too cold a temperature. It is only lukewarm at best. There is no problem with the pressure flow. I have tried turning up the water temperature on the boiler, but this does not affect the shower temperature in any way. I have also tried cleaning the shower head, but to no avail. Can someone please help me make my shower warmer?