I have a worcester danesmoor boiler with a Danfoss BFP 11 L3 pump on an electro oil inter 2011 burner. How is this fixed to the electric motor? Is it necessary to take the cover off the pump? Also, concerning the same oil pump, in an attempt to remove the solenoid, I mistakenly unscrewed the small allen screw in the centre, thinking that I could then withdraw the solenoid. Immediately oil started to leak out around the screw, which I later believed to be related to the internal oil filter. However, it was very difficult to stop the flow of oil when I retightened the screw. Is there an "O" ring seal which I may have damaged? It seems possible to continue tightening the screw much further than it's original position. Any advice gratefully received.