How can the safety valve on a steam boiler be tested?

Testing the safety valve on a steam boiler is a critical procedure to ensure that it functions correctly and can prevent dangerous overpressure situations. Lifting the lever or raising the pressure simulates a condition that allows the safety valve to open. This action verifies that the valve will operate as intended when the steam pressure exceeds the set limit. By witnessing the valve's response, the operator can confirm that it is not only capable of opening but also resealing properly after the test, which ensures that it will operate safely during actual conditions.

In contrast, removing the safety valve completely would not provide an effective test of its performance, as this might lead to a dangerous situation due to the inability to control steam pressure. Checking for leaks does not evaluate the valve's operational capability under pressure conditions. Visual inspection alone, while essential for maintenance, cannot confirm whether the valve will function properly in a high-pressure scenario, which is vital for maintaining safety standards in boiler operation.