Hi
Last night I used the immersion heater for 20 min to get some quick hot water (Usually I use the hot water from the exchanger of the CH system). Now even after the immersion was turned off for so many hours (but the central heating and hot water are on), the boss of the immersion (the part on top of the cylinder with a wire connecting the immersion to the electric switch) is still quite hot.
I wonder whether it is normal – The immersion has been switched off for more than 12 hours, why the boss is still hot?
Many thanks.