I had an outside underground tank on my oil furnace. It went south and could not be fixed by my oil furnace company. I installed a 275 gallon indoor tank. The oil pump had an intake and a return line on it when I had the underground tank. I was under the impression you did not need the return on the pump when you had a short run (and the tank did not have a place for a return to connect to) so we removed and plugged the return line. I fired up the pump and oil is spewing everywhere. Have I put too much pressure on the pump by not using a return line and blown all the seals? If so, how is a return normally routed into an indoor 275 gallon tank? Or is there a different pump I am supposed to use when I have a single supply line?
Inside the fuel pump is a set screw with an Allen head on it. It needs to be removed when only using a one pump system. However that doesn't matter at this point because the seal on the oil pump is now blown. You will need a new pump.