I have just had british gas replace my boiler with a combi boiler and I also have just had a Aqualisa Quartz shower installed (Not Pumped). I seem to have problems with the shower reaching temperature, When I turn the shower on the boiler fires up and the burner light is on but then the shower seems to cut off the hot water and the boiler switches off and this will keep happening until I turn the temperature down on the boiler or the shower which is on the cold side of the scale anyway. This also becomes more of a problem in the morning when the Central Heating is on. I have had british gas out who say there is nothing wrong with the boiler and I have had Aqualisa out and they say there is nothing wrong with the shower.