I had a new central heating system installeda couple of years ago and I now have a problem that the heating won't go off. I have a Honeywell CM67/61NG room unit and HC60NG relay box. I turn it off at the room unit but the boiler is still working and all the rads get hot. The little flame symbol on the room unit does not come on and the green light on the relay box does not come on but still the boiler is on and the rads get hot. Any ideas?