How far must a thermocouple be inserted over a pilot flame?

The correct insertion depth for a thermocouple over a pilot flame is typically between 3/8" to 1/2". This range is critical because it ensures that the thermocouple adequately measures the temperature of the pilot flame without being overly immersed, which could lead to inaccurate readings due to heat saturation.

Inserting the thermocouple within this range allows it to respond effectively to the heat produced by the pilot flame, providing reliable feedback to control systems that manage the overall combustion process. This level of sensitivity is important for ensuring safety and proper functioning in heating appliances, as it allows for timely adjustments based on the temperature readings.

In comparison, deeper insertion could cause the thermocouple to read temperatures that don't truly reflect the pilot flame's intensity, potentially resulting in poor performance or malfunctions in the appliance it serves. This accurate placement is crucial for maintaining the efficiency and safety of the heating system.