When should a water column and gauge glass be blown down normally?

Blowing down the water column and gauge glass is primarily conducted at the start of a shift and whenever there is an indication that the water level is not accurate. This procedure is essential for ensuring the accuracy of the water level readings, which are crucial for the safe operation of a steam boiler.

During the blowdown, stagnant water or debris can be cleared from the gauge glass and water column, allowing for a true representation of the water level in the boiler. If the gauge glass is not blown down periodically, sediments can build up, leading to inaccurate readings that may result in unsafe operating conditions, such as low water levels, which could cause overheating or damage to the boiler.

Thus, performing this procedure at the beginning of each shift ensures that the water level instruments are operating correctly right from the start of operations, and checking again whenever there are concerns about water levels helps maintain safety and efficiency throughout the operation. Regular maintenance checks, while important, should not be the only times that these instruments are verified.