We have a Slant Fin natural gas boiler which is about 10 years old. The pilot light will not stay lit at this point. Recent repairs beginning at the start of the heating season include 2 new thermocouplers, cleaning the pilot unit and bypassing the electric damper. Our gas bills were extremely high this year even allowing for the colder temperatures. The repair service indicated that we may now need a new valve for $300. I am wondering at this point if we would be better to replace the boiler with a more efficient unit or to continue to try to repair the old one.