Hi to you all, hopefully someone can help me with my problem, i have a Potterton Suprima 50, i have had the same problem with it for about a month now, when i have the hot water on the radiators come on also, the control for the heating will be off but they will still come on, i have had 2 different engineers come out one said that it was a faulty thermostat which was replaced but still the same problem, then the other one said it was something to do with a valve so that was replaced but im still having problems now today i've noticed that there is a small amount of water coming from the pipe that goes into the Potterton Suprima 50, i did call back the 2nd engineer but he cant come out until next week. has anyone got any ideas what it could be? Thank you.