A rising bulge level indicates which condition?

A rising bulge level indicates which condition?

• A. Pressure drop in main feed
• B. Valve jam
• C. Air ingress
• D. Gross leakage of firemain through suction valve

Answer: (D)

A rising bulge level points to leakage past the suction valve in the firemain system. When the firemain pump draws water, the suction line should stay primed and water should move smoothly from the sea chest through an intact suction valve. If the valve seal or packing is leaking, water from the firemain can escape into the suction side, causing the water surface in the bulge indicator to rise. This is a direct sign that the suction valve is not sealing properly, i.e., there is gross leakage through it. This is more indicative than a simple pressure drop in the main feed, which doesn’t specifically reveal a leak at the suction valve. Air ingress would typically cause air bubbles or inconsistent priming rather than a steady rise in the bulge level. A valve jam would hinder flow but wouldn’t necessarily produce the distinctive rising bulge signal tied to leakage around the suction valve.

A rising bulge level points to leakage past the suction valve in the firemain system. When the firemain pump draws water, the suction line should stay primed and water should move smoothly from the sea chest through an intact suction valve. If the valve seal or packing is leaking, water from the firemain can escape into the suction side, causing the water surface in the bulge indicator to rise. This is a direct sign that the suction valve is not sealing properly, i.e., there is gross leakage through it.

This is more indicative than a simple pressure drop in the main feed, which doesn’t specifically reveal a leak at the suction valve. Air ingress would typically cause air bubbles or inconsistent priming rather than a steady rise in the bulge level. A valve jam would hinder flow but wouldn’t necessarily produce the distinctive rising bulge signal tied to leakage around the suction valve.