What happens if a thermopile is not adequately covered by the pilot flame?

If a thermopile is not adequately covered by the pilot flame, it will fail to generate adequate output. The thermopile generates electrical current by converting thermal energy from the flame into electrical energy. For this conversion process to occur effectively, the thermopile needs to be exposed to a certain level of heat from the pilot flame. If the thermopile is not receiving enough heat because it is not properly positioned within the flame, its output will be insufficient to maintain the necessary operation of the system it supports, such as releasing additional gas or maintaining ignition.

The other options describe scenarios that would not occur under these circumstances. Overheating typically occurs when a thermopile is subjected to excess heat, which is not the issue when the flame coverage is inadequate. Damage to the thermopile is usually a result of extreme conditions rather than simply a lack of flame coverage. Additionally, operating at optimal efficiency contradicts the fact that insufficient flame coverage directly hinders its performance.