Question 60Motor Plants - 1st Asst/Chief

70% to pass

During maneuvering on a slow speed diesel engine vessel, a low starting air system pressure alarm is activated. Local starting air receivers' pressure gauges indicate proper pressures, and compressors are running and are 'loaded' up. What could cause the alarm?

AMalfunctioning starting air cylinder distributor valves.
BA stuck open air starting valve on one of the engine cylinders.
CMalfunctioning, stuck open, main engine air starting valve.
DFaulty system alarm pressure switch and/or a fault in the alarm circuit.
AI Explanation

The correct answer is D) Faulty system alarm pressure switch and/or a fault in the alarm circuit. The reasoning is that if the local starting air receiver pressure gauges indicate proper pressure and the compressors are running and loaded, then the issue is likely not with the starting air system itself, but rather with the alarm system that monitors the starting air pressure. A faulty pressure switch or a fault in the alarm circuit could cause the low starting air pressure alarm to activate even when the actual system pressure is within normal operating range. The other options (A, B, and C) would all involve issues with the starting air system components, which can be ruled out in this scenario.

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Official Resources
46 CFR Machinery & Electrical 46 CFR Engineering USCG National Maritime Center
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