Gas Fitter Practice Test

When is a low water cut off device required on a hot water heating boiler rated at 350,000Btuh?

1. Not required if a limit control is installed

2. Not required if it is installed in an industrial application

3. Required when any portion of the circulating system is located below the boiler

4. Required only in commercial applications

The correct answer is: Required when any portion of the circulating system is located below the boiler

A low water cutoff device is an important safety feature for hot water heating boilers, particularly those with significant output, such as one rated at 350,000 Btuh. This device is designed to prevent the boiler from operating when the water level is too low, thereby reducing the risk of overheating and damaging the boiler components. The requirement for installing a low water cutoff device arises particularly in situations where there is a possibility for the boiler to run dry. When any portion of the circulating system is positioned below the boiler, gravity can create a scenario where the water level could drop below safe operating levels due to siphoning or other factors. In such cases, to ensure safety and proper operation, the low water cutoff device becomes necessary as it acts as a safeguard to interrupt the heating process if water levels fall below a certain threshold. The other scenarios listed, such as having a limit control installed or the application being industrial, do not guarantee the same level of safety as having a low water cutoff in place. It's crucial in ensuring the boiler operates within safe conditions, particularly in systems where low water levels could occur due to piping configurations. In commercial applications, while similar considerations apply, the specific requirement for low water cutoff devices indeed depends broadly on system design and the potential for