For which type of boilers is a low-water cutoff not required under certain conditions?

A low-water cutoff is a crucial safety device used in various boiler systems to prevent the boiler from operating when there is insufficient water, which can lead to overheating and potential damage. However, certain types of boilers have different operational characteristics that may make a low-water cutoff less critical or not required under specific conditions.

Coil-type and water-tube-type boilers are designed with specific engineering that allows for more efficient heat transfer and steam generation. These boilers often operate under different conditions compared to other types, such as steam boilers. For instance, they are typically smaller and may have faster recovery times due to their design, which can reduce the likelihood of low water conditions impacting safe operations. Additionally, many of these systems are designed to minimize water in the boiler’s steam-generating section, which may mitigate the risk of running low on water.

It is this combination of design and operational efficiency that leads to the conclusion that for coil-type and water-tube-type boilers, a low-water cutoff may not be required under specific operational scenarios. This is typically based on the manufacturer's recommendations, installation practices, and the overall hazard assessment of the installation. Understanding the engineering principles behind these boilers allows operators to make informed decisions about safety devices like low-water cutoffs.