What is the proper sequence of opening and closing blow off valves while blowing down the boiler?

When blowing down a boiler, the proper sequence is to first open the blow-off valve slowly to allow for a controlled release of pressure and water, followed by opening the blowdown valve. After the blowdown is complete, close the blowdown valve first, then close the blow-off valve. This sequence helps prevent potential damage and ensures safe operation by managing pressure changes effectively.