Hi I have a gravity fed system y plan system, hot water tank in airing cupboard. Due to the fantastic warm weather I haven't turned on the heating whatsoever. Over 2 weeks ago I set the hot water on for a few hours for washing dishes etc. I still have hot water coming through the taps. Is this normal? I would think by now the hot water would be all used. I know the boiler is not firing and the pump is not running. Immersion heater is off Any ideas... thanks.