I have a conventional, fully pumped central heating/hot water sytem via a gas boiler and with a hot water storage tank. I have turned off the CH for the summer but kept the HW off the boiler. However when the boiler heats up the tank it also heats up the radiators.
The motorised valve on the CH sytem works OK because it is hot on the boiler side and cold on the other side. However i can feel water vibrating (circulating?) through that side. Could there be some other point where there is a cross flow between the CH and HW systems.
Thank you
Terry R