Why chemically clean?

The build up of scale and other deposits in boilers, heat exchangers, cooling towers and system pipe work reduces efficiency of the equipment. In the case of steam boilers this can cause the boiler to be dangerous to operate. On-line chemical cleaning or in exceptional circumstances acid cleaning may have to be considered in order to remove these the deposits as a method of restoring the heat transfer efficiency.
Calcium, magnesium and silica scales which build up on boiler heat exchange surfaces act as an insulator which results in an increase in temperature of the boiler metal. Unless treated or removed the scale will cause the metal to overheat resulting in blisters and eventually tube or furnace failure. The effect on the boiler efficiency can be seen from the following table.

Thickness of Boiler Deposit mm

• 0.85 mm
• 1.0 mm
• 1.3 mm
• 1.6 mm
• 2.3 mm
• 2.8 mm

Fuel Wasted %

• 7%
• 9%
• 11%
• 13%
• 15%
• 16%

When should a system be acid cleaned ?

Boilers - usually, with boilers the insurance inspector will fail a boiler if it considered to be in a dangerous condition and will not allow the boiler to operate until cleaned satisfactorily. For higher pressure boilers chemical cleaning may also be carried out to restore heat transfer efficiency and this decision may be taken by maintenance personnel in conjunction with their water treatment company.