Rock the Gas Heat ESCO Exam 2025 – Fire Up Your Future in HVAC!

The thermocouple is a crucial safety device used in gas appliances that have a pilot light. Its primary function is to monitor the pilot flame. When the pilot light burns, the heat from the flame generates a small voltage within the thermocouple, which keeps the gas valve open, allowing gas to flow to the burner.

If the pilot light goes out, the thermocouple cools down, resulting in the loss of voltage. This drop in voltage signals the gas valve to close, effectively preventing gas from flowing into the burner. This safety feature is critical as it minimizes the risk of gas accumulation, which can lead to hazardous situations such as fire or explosion.

In contrast, the other options play different roles in the operation of gas systems. The thermostat regulates temperature and controls the operation of heating systems, the gas regulator manages the pressure of the gas entering the appliance, and the draft inducer is responsible for creating a draft to ensure proper venting of combustion gases. These components do not directly provide the same level of protection against gas flow if the pilot light is extinguished.