Upon arrival added sludge additive to the oil fill pipe for one oil tank. Went inside and removed a plug from the second oil tank and added the sludge additive to the second tank. Put the plug back in the second oil tank. Replaced both oil filters and found the one for the first tank was very dirty and was starting to restrict oil flow coming out of the tank. Bled the oil line leading to the burner and had clean and consistent oil flow coming out.