A lot of temperature problems can be caused by blockages in the sprayplate of your shower head, often caused by limescale build up. Try cleaning it with a descalent solution or some lemon juice and a nail brush. You may also have the shower turned up too high which is caused the thermal cutout to switch the heat on and off. Try turning the temperature down a bit. If all else fails try ringing Mira's Service Department on 0844 571 5000 who will be able to help you.
Bob The Builder, January 2011
