Sorry for not getting back sooner, thanks for name acceptance. If your heating was either on or off is irrelevant as it is purely the thermostatic valve that is the problem, and if you have an open feed tank then the water would run as long as room temp. required the valve to call for heat. If pressurised system the water would stop as soon as the content of the system was empty. Conversely the valve could could close again when the room temp up. Regardless of all that it is not you or the valve that is at fault, it is the person that did not plug off. Just remember we can all make mistakes. Cheers
Hard@it