We had a gas boiler removed in a section of our school. This boiler used to heat showers and water that supplied 2 pupils toilets. It had a 200l calorifier it heated. The showers and toilets were removed over a year before, and the boiler was still heating water but only supplying 3 infrequently used taps. 

We had the boiler and calorifers removed and had POU heater fit on the 3 taps it still heated.