When a burner fails to ignite during the ignition trial period, what must be done before the boiler can be restarted?

When a burner fails to ignite during the ignition trial period, it indicates a malfunction that often triggers a safety mechanism designed to prevent accidents. In this context, the burner will enter a "lock-out" state to ensure that it cannot attempt to ignite again until the issue is addressed. Therefore, manually resetting the lock-out switch is an essential step before the boiler can be restarted.

This process is crucial because the lock-out feature is implemented to protect the boiler and its operator from potentially dangerous situations, such as unburned fuel accumulating in the combustion chamber. Once the lock-out is reset, operators can then proceed to troubleshoot or inspect other components (if necessary) to ensure safe operation. Resetting the lock-out ensures that the system returns to a state where it can safely attempt ignition again, provided all conditions are verified to be correct.