Miss a crack in your boiler refractory and you could be chasing flame instability or a warped door before the season's over. Here's exactly what to inspect—and what to do about it. Jude walks through a real boiler inspection covering rear door refractory condition, turnaround chamber brickwork, burner refractory, gasket replacement, and the critical post-startup bolt check most techs skip. Refractory damage affects flame shape, boiler efficiency, and front-end overheating. Skipping the gasket swap or forgetting to re-snug bolts after warmup can blow a door seal and cause serious damage—fast. Safety notice: Always consult experts for complex repairs. Weekly Boiler Tips are compiled by the knowledgeable and remarkably prolific content creators at WARE, a family owned, third-generation, 69-year-old commercial and industrial boiler rental and service firm based in Louisville KY. You can learn all about this and more at WARE's Boiler University.