HI, Ive taken off a thermostatic radiator. No problem until I noticed the pressure on my combi had dropped to zero. When I tried to re pressurise the system water started leaking out of the pipes left where the radiator was. We had put brass caps on the pipes left as a precaution as we thought that thermostatic radiators had a close off valve. So why is it leaking? I have now emptied the whole system so am hoping nothing will leak now!