it sounds to me as though the pump is not circulating, vent the pump through the screw at the front. and vent all rads and bleed taps any where on system untill it is working. some times its better to let things settle 1st for a night or so then bleed everything again untill its working. if the rads/system/ boiler are full then its not a blocked cold feed. sometimes the boiler can get airlocked depending on its position.hope this helps. you may have to drain and refill
john
February 2009