While evaluating a gas valve that failed to open, if continuity is present and proper voltage is at the terminal, what should be checked next?

When evaluating a gas valve that has failed to open, and you've confirmed that there is continuity and proper voltage at the terminals, the next logical step is to check the limit switch. The limit switch is a critical safety component that regulates the operation of the gas valve and can prevent it from opening if certain safety thresholds are exceeded—like overheating.

If the limit switch is open due to a safety concern, the gas valve will not receive the signal it needs to activate, regardless of the voltage and continuity present. By checking the limit switch, you ensure that the safety circuits are functioning correctly and that the system is being allowed to operate safely. This step is crucial in diagnosing whether the issue lies with the gas valve itself or with an upstream component that is designed to protect the system from unsafe conditions.

Understanding the role of the limit switch aids in correctly troubleshooting the entire heating system while maintaining adherence to safety protocols. This approach helps to narrow down the source of the problem efficiently, ensuring that any necessary repairs or adjustments can be made appropriately.