What is a common sign of a malfunctioning limit switch in an HVAC system?

A common sign of a malfunctioning limit switch in an HVAC system is constant fan operation. The limit switch is designed to regulate the temperature and ensure that the system operates within safe limits. If it fails, it may continuously signal the fan to run, regardless of whether the system is heating or cooling, leading to the fan operating constantly.

In this context, if the limit switch is stuck in the "on" position, the fan will not cycle off as it should when the desired temperature is reached. This can exhaust the system and potentially lead to further issues, such as increased energy consumption and discomfort in the living space. Understanding the function of the limit switch is crucial for diagnosing HVAC problems, making it easier to ensure proper operation and efficiency in heating and cooling systems.