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I have a 10 year old Buderus triple-pass, three section, cold start boiler. It either has a leak in the gasket between sections or a fissure in one of the section castings. It does not drip, but has probably been defective since new. I only recently became aware of the problem because the outer blue metal jacket corroded through. The insulation jacket is all black with mold from the misting of the leak making exact location difficult, but I have it down to a 4 inch circle. Buderus will provide a new boiler block but I must bear the $2400 charge for installation. Is there a stop-leak product that I can introduce into the boiler or a boiler cement that can be used on the outside to repair this? Lacking either of these solutions, is there a reliable home boiler repair outfit that I can use? I live in Snyder Co. central PA.