G2 Gas Fitter Practice Exam

What is the primary purpose of a low water cut-off device on gas-fired boilers?

1. To enhance system efficiency

2. To maintain temperature

3. To shut off the burner in the event of an unsafe water level

4. To modulate gas flow

The correct answer is: To shut off the burner in the event of an unsafe water level

The primary purpose of a low water cut-off device on gas-fired boilers is to shut off the burner in the event of an unsafe water level. This safety device plays a crucial role in preventing the boiler from operating dry, which can lead to overheating and potential damage to the boiler or even catastrophic failure. When the water level drops below a predetermined threshold, the low water cut-off detects this condition and automatically interrupts the fuel supply to the burner, safeguarding the system from hazards associated with low water conditions. This safety measure is crucial because boilers rely on water to transfer heat and to create steam. If the water level is too low, the heat generated by the burner can cause the metal surfaces to overheat, leading to structural failures. Therefore, the low water cut-off device is an essential component that ensures safe operation and prevents dangerous situations in gas-fired boilers.