A mate of mine as an heatslave boiler 12/14 i think. He had recently run out of oil without realising. Since the oil tank as been refilled the boiler lockout light comes on after around 2mins of switching the boiler on. Then if you switch the boiler on soon afterwards the lockout light comes on after about 20 seconds. After leaving the boiler for a longer period of time it takes around two minutes for the lockout light to come on. Weve checked the oil line which had a lot of sediment/sludge from bottom of tank. We disconnected a pipe under the house(static caravan)and cleared any remaining debris. Weve disconnected the oil feed at the boiler and oil runs ok so we dont think it is this that is causing the problem but not sure.the boiler was running fine before it ran out of oil. Could it be a problem with the pump or anything else any suggestions would be appreciated