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    July 30, 2020 3 min read

    Why Hard Water is Not Used in Boilers?

    Hard water contains dissolved salts of calcium and magnesium. It forms scales (also called lime scales) on the walls of the boilers and hence to be softened before its usage in industries. These scales reduce the heat conductivity of boilers some times leading to the breakdown. 

    One of the leading causes of poor boiler performance is improper water treatment. Improper water treatment, or not treating your boiler water at all, can cause irreversible boiler tube damage called scaling. To avoid scaling, boiler water should be circulated through a water softener before it is fed to the boiler. A water softener removes hard water minerals, like calcium and magnesium, which can cause scaling and damage in the boiler tubes. Acting as an insulator, scale deposits can prevent proper heat transfer, decrease boiler efficiency, and lead to costly downtime and even premature boiler failure. 

    What are the problems faced in a boiler when hard water is used?

    water boiler hard water

    Hard water that’s filled with minerals like calcium and magnesium can cause damage to the tubes inside water boilers. If these minerals are present in the boiler’s water supply, it can lead to limescale forming on the surface of the tubes, which has the potential to cause overheating and tube failure.  

    The efficiency of a boiler can also be negatively affected by hard water. If the presence of calcium and magnesium causes hard scaling, it will have an impact on the heat transfer inside the boiler. A layer of hard scaling as small as 1/8 inch on boiler tubes can decrease efficiency as much as 25 percent. This will only make the boiler work harder and consume more fuel in order to meet your steam needs.

    Hard water can cause a range of problems, not only with your boiler, but also with your central heating system in general. This is because the dissolved ions are left behind when the water is heated to steam. The remaining ions bond to form calcium carbonate, aka limescale. This limescale coats pipes, the heating element, and even blocks up your radiator!

    Within the boiler, limescale can form on the heating element, which makes it more difficult for the boiler to heat the water efficiently. As a result, the boiler needs to use more energy, and more fuel to power your central heating system.

    Inside the pipes, limescale deposits not only block up the pipes and prevent the smooth flow of steam and water, they can also cause issues with thermal conduction. Again, this will mean that your boiler has to work harder, costing you more in fuel bills. In addition, calcium carbonate can build up inside the radiator. This means that your radiators will develop cold spots, and your home will feel colder.

    You are likely going to see the cost associated with heating your home spike. Plus, your system will suffer more wear and tear than it otherwise would, which can lead to an increased risk of damages.

    Why is Water Softened before using in Boiler?

    The solution to these potential problems is a water softener working in conjunction with your boiler. Water softeners will introduce sodium compounds into the boiler’s water supply to negate the presence of any calcium and magnesium, effectively resolving the hard water problem. A water softener will reduce the risk of hard scaling inside the boiler, improve the flow of water, ensure maximum levels of efficiency, and help your boiler avoid failures or any kind of damage that could reduce its lifespan.

    It is important to supply your boiler with soft water at all times to avoid damage and costly repairs. Water softening can lead to many years of reliable boiler system performance!


    So can I use softened water in my boiler? Well, we recommend that the best way to avoid the damaging effects of hard water on your boilers is to install a water softener. Contact us today if you have hard water, or suspect that hard water is negatively affecting your boiler. Aquatell can help you find the appropriate balance in your home's water quality.