USCG Exam PracticeWatch duties, terminology, and instrumentation
The gauge glass on a boiler drum is connected to the steam space at the top and the water space at the bottom. Why must the gauge glass be blown down during each watch?
- A. To cool the glass connections and prevent thermal cracking of the sight glass
- B. To drain accumulated sludge from the drum bottom before taking a water-level reading
- ✓ To clear the connections and confirm the level returns promptly, ensuring the glass is not stuck or reading falsely highCorrect
- D. To activate the low-water fuel cutout and verify it trips the burners at the correct level
Why C is correct
NAVEDTRA 14104 §4-2 states the gauge glass must be proved reliable by blowing it down on watch — opening the drains to clear the connections and confirm the level returns promptly and reads truly — so a stuck or falsely high reading cannot mask a real low-water condition. A falsely high reading is the specific hazard the blowdown procedure guards against.
Cited:NAVEDTRA 14104 §4-2