Gas Fitter Practice Test

When a pilot light intermittently goes out, which is the next step if the millivolt test is steady at 14 millivolts?

1. Replace the gas valve because the magnet is weak

2. Clean and adjust the pilot and burners

3. Replace the thermocouple

4. Check for another problem such as down draft or pilot position

The correct answer is: Check for another problem such as down draft or pilot position

When the millivolt test reads a steady 14 millivolts, it indicates that the thermocouple is functioning adequately, as it is generating enough voltage to keep the gas valve open. In this situation, the next logical step is to investigate external factors that could be affecting the pilot light. Checking for other problems such as a down draft or the pilot position is crucial because these issues can cause the pilot light to blow out intermittently. A down draft can be caused by factors such as a blocked vent or improper installation of the venting system, which may disrupt airflow and extinguish the pilot light. Similarly, if the pilot light is not correctly positioned, it might not stay lit due to insufficient flame contact with the thermocouple. By systematically addressing these possibilities, you can resolve the issue without unnecessarily replacing parts like the gas valve or thermocouple, which are not indicated by the millivolt reading. Understanding these external factors will help in diagnosing and fixing the problem more effectively.