Water contains certain percentage of dissolved solids. The percentage of impurities found in boiler water DEPENDS on the untreated feed water quality, the treatment process used and the boiler operating procedures. As a general rule, the higher the boiler operates pressure, the greater will be the sensitivity to impurities. As the feed water materials EVAPORATE into steam, dissolved solids concentrate in the boiler either in a dissolved or suspended state. Above a certain level of concentration, these solids encourage foaming and cause carryover of water into the steam. This leads to scale formation inside the boiler, resulting in localized overheating and ending finally in tube failure. It is therefore necessary to control the level of concentration of the solids and this is achieved by the process of ‘blowing down’, where a certain VOLUME of water is blown off and is automatically REPLACED by feed water – thus maintaining the optimum level of TOTAL dissolved solids (TDS) in the water. Blow down is necessary to protect the surfaces of the heat exchanger in the boiler.

Water contains certain percentage of dissolved solids. The percentage of impurities found in boiler water depends on the untreated feed water quality, the treatment process used and the boiler operating procedures. As a general rule, the higher the boiler operates pressure, the greater will be the sensitivity to impurities. As the feed water materials evaporate into steam, dissolved solids concentrate in the boiler either in a dissolved or suspended state. Above a certain level of concentration, these solids encourage foaming and cause carryover of water into the steam. This leads to scale formation inside the boiler, resulting in localized overheating and ending finally in tube failure. It is therefore necessary to control the level of concentration of the solids and this is achieved by the process of ‘blowing down’, where a certain volume of water is blown off and is automatically replaced by feed water – thus maintaining the optimum level of total dissolved solids (TDS) in the water. Blow down is necessary to protect the surfaces of the heat exchanger in the boiler.