Boiler and Steam System Troubleshooting — real-world interview & field troubleshooting questions with clear, practical answers. Tap any question to open its answer. Showing the first 70 questions free. The complete question bank is available as a PDF below. BOILER WATER LEVEL, GAUGE GLASS & LOW-WATER CUTOFF (LWCO) Q1 An operator notices that the boiler gauge glass is completely clear and shows no water meniscus. What is the immediate life-safety procedure? Answer Perform an immediate blowdown test of the gauge glass column to determine whether the boiler is completely full (flooded) or dry (severe low water). If water does not appear immediately upon closing the drain, execute an Emergency Fuel Trip (EFT). NEVER pump cold feedwater into a red-hot dry boiler. Q2 The water level in the gauge glass appears motionless and shows zero dynamic bobbing while the boiler is steaming heavily. What is blocked? Answer The lower water-side or upper steam-side isolation valve port ...