Question 32 OSE01 - Chief Engineer - OSV

The Correct Answer is A ### Explanation for Option A (Correct) **A) The float switch wire connections are loose at the terminals, not permitting continuity through the switch.** This is the correct answer because of the fundamental electrical logic of the alarm system described: 1. **Normal Condition:** The switch is closed (continuity exists), keeping the alarm de-energized (OFF). 2. **Alarm Condition (Low Level):** The switch is designed to **open** (loss of continuity), which triggers the alarm circuit (ON). A loose connection or a broken wire simulates the exact electrical condition required to trigger the alarm—it creates an open circuit (loss of continuity) in the monitoring line. Even though the actual water level is normal and the float is up (meaning the physical switch contacts should be closed), the faulty wiring means the electrical signal never completes, fooling the alarm panel into thinking a low-level condition exists. --- ### Explanation for Other Options (Incorrect) **B) The float level switch contacts are welded closed, not permitting the contacts to open.** If the contacts are welded closed, the switch maintains continuity (a closed circuit) regardless of the water level. Since the alarm requires the circuit to *open* to activate, a welded switch would prevent the low-level alarm from ever sounding, even if the level truly dropped. It would not cause a false alarm when the level is normal. **C) The float is binding in the float chamber, not permitting the float to drop.** Since the actual water level is normal, the float is correctly positioned in the "up" position. In the "up" position, this type of switch is designed to be **closed** (continuity). If the float is binding in this high position, it simply ensures the switch stays closed, which prevents the alarm from activating. This condition would mask a true low-level event but would not cause a false alarm when the level is normal. **D) It is not possible for a low coolant level alarm to occur when the water level is normal.** This is incorrect. False alarms frequently occur due to electrical faults, such as wiring issues, power spikes, or faulty sensing components (like the loose connection described in option A). A mechanical fault (C) or a fault in the alarm logic or sensor wiring (A) can easily trigger an alarm when the physical condition (water level) is normal.