What is an essential task prior to starting a steam boiler?

Checking the water level is an essential task prior to starting a steam boiler because maintaining the proper water level is crucial for safe operation. If the water level is too low, it can lead to overheating and damage to the boiler, potentially causing a dangerous situation such as a boiler explosion. Conversely, an excessively high water level can result in water carrying over into the steam system, which can lead to inefficiencies and operational issues. Therefore, ensuring that the water level is within the appropriate range is a fundamental step in preparing a steam boiler for operation, as it directly impacts not only the efficiency but also the safety of the system.

In contrast, tasks such as filling the boiler with oil or inspecting the ignition system, while important for specific types of boilers or burner systems, are not universally applicable and critical in every situation before starting a steam boiler. Clearing the blower, while a good maintenance practice, may not be directly relevant to checking the readiness of the boiler in terms of water level and safety.