Which type of control would be used to prevent the system from overheating?

Using high limit control is essential for preventing overheating in HVAC systems. This type of control is designed to monitor the temperature of the system and will shut down or limit the operation of the heating element if the temperature exceeds a predetermined threshold. This safety mechanism is crucial to protect equipment and ensure safe operation, as overheating can lead to equipment failure, fire hazards, and reduced efficiency.

High limit controls are commonly found in heating systems, such as furnaces and boilers, where maintaining safe operational temperatures is vital. When the temperature exceeds the set high limit, the control activates, either turning off the heating source or modulating it to bring the temperature back within safe limits.

In contrast, other control types address different operational needs. Low limit control is designed to ensure that the heating system operates at or above a minimum temperature but does not specifically focus on preventing overheating. Pressure control relates to the management of system pressures, which is important but does not directly address temperature regulation. Proportional control adjusts the output based on the difference between the setpoint and actual temperature but might not provide the immediate cut-off that high limit control offers in cases of overheating.