HVAC Unlimited Heating, Piping, and Cooling (S-2) License Practice Test 2025 – All-in-One Guide to Master Your Exam!

The component that controls the burner operation in a residential gas boiler is the high limit control. This device ensures that the water temperature does not exceed a predetermined level, preventing overheating and potential damage to the system. When the water temperature reaches the set high limit, the high limit control will interrupt the operation of the burner, stopping any further heating.

In contrast, the other options serve different roles in the overall system. The thermostat regulates the temperature of the space by controlling when the heating system operates based on the desired indoor temperature. The low limit control is designed to maintain a minimum water temperature, preventing the boiler from operating below safe and efficient levels. The float switch is typically related to water level control in systems, ensuring that there is sufficient water in the boiler to operate safely, but it does not directly regulate burner operation.

Understanding the specific functions of these components is crucial for troubleshooting and maintaining residential gas boiler systems effectively.