Remove old gasket and thoroughly clean surface on boiler and on cover plate. If the gasket being replaced is not a Topog-E gasket it may be necessary to buff each surface. Place new Topog-E gasket on inspection cover plate, and make sure that the gasket is pushed down tight on the plate. Do not use any grease, lubricant or adhesive. When the cover plate is in the boiler and the gasket is in place, make one last cleaning swipe using a rag wrapped around your finger to ensure the mating surface in the boiler is clean.
Set crab, then center plate in opening and tighten nut enough to give a snug fit. Make it hand tight then increase pressure on the gasket with a quarter turn of wrench.
Do not over-tighten as it will over-compress the gasket and shorten its service life. If gasket leaks while pressure is being built up, tighten only enough to stop leakage.
As pressure builds up to operating level in the boiler, the nut and crab will loosen as it typically takes several days for the gasket to reach its ultimate compression. It is important to keep the nut at least finger tight until it no longer loosens.