When is the best time to blow down the boiler?

The best time to blow down the boiler is when it is at its latest load. This timing is crucial because when the boiler is operating at its typical load, it is more stable in terms of pressure and temperature. The blowdown process, which involves removing a portion of the water from the boiler and replacing it with fresh water, is aimed at controlling the concentration of dissolved solids. When the boiler is at its latest load, the water is more conducive to maintaining the proper balance of chemistry since it has been actively managing the steam and water separation processes.

Blow down at this point helps ensure that any impurities or concentration of salts, which may have built up during operation, are effectively removed without causing significant upsets in the boiler's performance. Additionally, this method minimizes thermal shock to the boiler system and maintains proper water levels, which is essential for safe operation.

Contrastingly, blowing down at low load or during cooling might not effectively remove the impurities as the water chemistry could be altered, and the dynamics of the boiler are less stable. Performing the blowdown at high load can create stress within the system that might lead to operational issues or damage. Thus, performing the blow down when at the latest load is the most efficient and safest practice.