How much of the thermocouple tip should be covered by the pilot flame?

The appropriate coverage of the thermocouple tip by the pilot flame is essential for accurate temperature readings and effective operation of gas appliances. Covering one third to one half of the thermocouple tip ensures that the thermocouple is exposed to enough heat to accurately sense the presence of the flame without excessive exposure that might lead to inaccurate readings or damage.

When the thermocouple is positioned correctly with this level of coverage, it allows for optimal heat conduction, ensuring the device can detect the pilot flame's presence effectively. This range allows for sufficient thermal response to maintain the safety and functionality of the gas system.

If the tip is covered too little, there might not be enough exposure to reliably detect flame presence, potentially leading to unsafe conditions or failure of the system to operate correctly. Conversely, covering too much of the tip may lead to overheating or malfunction of the thermocouple itself, affecting its lifespan and reliability. Therefore, the specified coverage of one third to one half is a balanced approach that promotes safety and functionality.