Do idle boilers (i.e. when boilers are not in use) require protection against corrosion ?
Yes, idle boilers requires protection, otherwise they can corrode badly. It has been found that with improved cleanliness of boiler surfaces the metal is prone to oxygen attack giving rise to pitting corrosion. Boilers which are idle for even such short time periods as weekends are susceptible to attack. Therefore it is necessary to protect the boiler against corrosion by employing suitable storage methods. When the boiler is not in use it should be cleaned if necessary and filled to the normal water level with deaerated feed water. By addition of chemicals a minimum of 400 ppm of P Alkalinity and 100 ppm of Sulphite is preferable. Alternatively catalyzed Hydrazine and neutralizing amine may be added to maintain 200 ppm of hydrazine and a pH of 10 in the boiler water. After the chemicals are added the water should be circulated for thorough mixing. The boiler water should be tested regularly at least once a week with treatment being added as necessary to maintain minimum treatment leve
