Hi There, this is my first post and am hoping to find the answer to my problem, i have a pump next to my storage tank that will not stop running. I think the pump is for circulating the water around the central heating circuit and the hot water circuit. yesterday morning we used the boiler to top up our hot water which i used the 1 hour boost on the time controller. we got the hot water ok but noticed 7 hours later the pump was still running. The only way i can stop it is to isolate the power supply next to the time clock and hw and ch controller. there is also a thermostat on the side of my storage tank which is a megaflow cl210 on what i think is a sealed unvented system. there are also 2 x 2 port valves on this system and a room thermostat. could anyone help me to locate the reason? we think this may have happened some time ago as well but today after switching the power back on the problem seems to have self rectified for now!! any advice much appreciated, thanks.