With the boiler temperature setting high, the mixure setting tap in the shower is only required to allow a small amount of hot water in from the boiler to achieve the correct temperature for the person having a shower. This can sometimes make the boiler think that the hot tap is off and so switches off.
Turn down the boiler temperature setting, which means the shower mixure tap can be turned to allow more water flow from the hot water pipe.
This means less cold water is being used to mix in with the hot water to get the desired temperature. The boiler therefore stays on because it senses a larger drop in pressure in the hot water pipes which implies demand for hot water.
shah, March 2013
