Hi, My aga is not getting enough oil through. The BM control box isn't filling up correctly. I removed the long filter and tested the flow and it only dribbles out. Is there any way of sucking the oil through? I haven't removed the fire valve yet but this could be the problem. There's plenty of oil in the oil lifter and the tank. I've tried to suck through but not very successfully. Any tips, or should I remove the fire valve and see if that is the problem?