Hi, My kitchen radiator stays cold when all the others in the house are warm. We used to have a 1000mm radiator but we reduced it to a 300mm and now the new radiator wont warm up. I've tried bleeding it, adjusting the lockshield valve and thermostat valve, i've replaced both valves, i've rebalanced the system but still no luck. the water that comes out of the radiator is clear but cold (when the heating is on) when I shut the lock sheild and thermostat valves on all the radiators in the house one of the pipes on the none working radiator gets warm but the other pipe stays cold as does the radiator, please help