Final answer:
The purpose of a low limit control on a hot water heater is to ensure that the temperature in the boiler does not drop below a certain threshold. This control helps prevent the water heater from operating at dangerously low temperatures and maintains a safe and efficient operation of the system.
Step-by-step explanation:
The purpose of a low limit control on a hot water heater is to ensure that the temperature in the boiler does not drop below a certain threshold. This control helps prevent the water heater from operating at dangerously low temperatures, which could lead to various issues such as reduced efficiency, increased energy consumption, and even freezing of the water pipes.
For example, let's say the low limit control is set to 100 degrees Fahrenheit. If the temperature in the boiler drops below this limit, the control will activate the burner and bring the temperature back up to the desired level. This not only ensures a steady supply of hot water but also helps prevent damage to the system.
It's important to note that low limit controls are commonly used on hot water heaters, contrary to the option mentioned in the question. They play a crucial role in maintaining a safe and efficient operation of these systems.