Please Help, I have had a bubbling noise resounding through the central heating radiators for a while and it looked like what was needed was the system flushing and refilling with an additive. This I did last week which solved the problem. Now I have a new one. over the weekend the heating and water are both cold, the pilot light is still lit, the room thermostat clicks on but the boiler doesn't fire up. The boiler thermostat clicks at 0 but nothing, please can any one help as penguins are nocking at the front door....