What is the purpose of connecting a millivolt meter to a gas heating thermocouple?

Connecting a millivolt meter to a gas heating thermocouple serves the important purpose of measuring voltage. A thermocouple generates a small voltage that is directly related to the temperature difference between its two junctions, typically measuring in the millivolt range. This voltage is produced as a result of the thermoelectric effect, where heat generates a small electric potential.

By using a millivolt meter, technicians can determine whether the thermocouple is functioning properly by checking if it produces the expected voltage for a given temperature. This measurement can indicate if the thermocouple is in good working condition and if it is accurately reflecting the temperature of the flame or the combustion process in the gas heating system. Proper voltage readings are crucial for the safety and efficiency of gas heating systems, as they help ensure that the pilot light and main burners operate correctly, leading to safe heating operations.