The process of clearing mineral scale accumulation from internal boiler surfaces, mainly calcium, magnesium, and other dissolved solids, is known as boiler descaling. These deposits eventually create hard, insulating layers that speed up equipment wear, increase fuel consumption, and decrease heat transfer efficiency. Descaling is necessary to maintain thermal performance, safety, and operational longevity in systems that are commercial, residential, or industrial. Regular descaling is an essential part of preventive maintenance because commercial boilers must maintain an efficiency of 81–88%. From combi, electric, and condensing systems to fire-tube and water-tube boilers, it reduces the chance of expensive repairs and guarantees consistent output.

What is Boiler Descaling?

A boiler is a container that holds water and uses heat to create steam or hot water. After that, the steam or hot water can be used for heat, sterilization, energy, and other purposes. Gas or oil are the fuel sources for the majority of commercial boilers.
According to the Department of Energy, in order for a boiler to function at a commercial level, its minimum efficiency requirements must fall between 81% and 88%.
Descaling is essential to preserving the integrity and health of boilers. Frequent boiler maintenance, which nearly always involves some descaling, saves money and hassle because a clean boiler will have fewer issues than a dirty one.

Boiler Types:

• Fire-Tube Boiler:

These boilers use tubes to transport hot gases from the furnace through chambers filled with water. Steam is created when the water absorbs the heat from the gases. Applications requiring low to medium pressure are typically served by these boilers.
Because scale deposits can build up on the inner surfaces of the tubes over time, descaling is crucial for fire-tube boilers. Usually made up of minerals like calcium and magnesium, these deposits decrease the effectiveness of heat transfer and can cause overheating. Descaling preserves the boiler’s overall efficiency, guarantees ideal heat exchange, and guards against possible equipment damage.

• Water-Tube Boiler:

In a water-tube boiler, combustion gases heat the water as it passes through tubes. Because of their efficiency and capacity to manage higher steam pressures, water-tube boilers are frequently utilized in high-pressure applications.
Descaling removes scale buildup on the outside of the water tubes, which prevents effective heat transfer. These mineral deposits, which are mostly made up of calcium and magnesium, can cause overheating and decreased boiler efficiency. Descaling helps preserve the overall efficiency of water-tube boilers, guarantees ideal heat exchange, and guards against equipment damage.

• Combination boilers

Combination boilers, also known as combi boilers, are a single unit that combines the capabilities of a central heating boiler and a water heater. They eliminate the need for a separate water tank by providing hot water for household and heating purposes.
For combination boilers, descaling is essential because it keeps scale deposits from building up on heat exchangers, guaranteeing effective heat transfer and preserving system performance. These scale deposits are frequently made of possible issues. In combi boilers, descaling guarantees a steady supply of hot water, helps maximize heat exchange, prevents minerals like calcium and magnesium, and can result in lower energy efficiency system inefficiencies.

• Condensing Boilers

By recovering heat from the flue gases that would otherwise be lost in a non-condensing boiler, condensing boilers are made to operate as efficiently as possible. They are renowned for efficiently turning fuel into heat that can be used.
Condensing boiler descaling maximizes transfer efficiency by removing scale deposits that can build up on heat exchanger surfaces. Scale, which is frequently made up of minerals like calcium and magnesium, can impede the condensing process and lower the boiler’s overall efficiency. Descaling helps condensing boilers operate at their best, save energy, and last longer.

• Electric boilers

Electric boilers produce heat by using electricity. In places where natural gas or other fuel sources are not easily accessible, they are frequently utilized. For small-scale heating applications, electric boilers are frequently utilized.
In order to ensure effective heat transfer and avoid overheating, the descaling process eliminates scale deposits that may accumulate on electric boiler heating elements. These deposits, which are frequently made of minerals like calcium and magnesium, may cause the heating elements to become damaged and result in decreased energy efficiency. Descaling extends the life of electric boilers, keeps them operating at peak efficiency, and reduces energy waste.

• Steam Boilers

Steam boilers generate steam for use in heating applications or other industrial processes. They are frequently found in manufacturing facilities, refineries, and power plants and can be either fire-tube or water-tube boilers.
Because it removes scale deposits from the heat exchange surfaces, descaling is an essential part of steam boiler maintenance. This guarantees effective heat transfer and avoids problems like overheating or decreased steam production. Usually made up of minerals like calcium and magnesium, scale deposits can result in higher energy usage and less dependable systems. Descaling prolongs the life of steam boilers, prevents energy waste, and maintains optimal steam production.

• Hot Water Boilers

The purpose of hot water boilers is to generate hot water for industrial processes, home use, or space heating. They are available in a variety of designs, such as water-tube and fire-tube.
Scale buildup on hot water boiler heat exchangers is eliminated by descaling. By doing this, problems like decreased heating capacity or equipment damage are avoided and effective heat transfer is guaranteed.

How to Avoid Scale Buildup in the Boiler

The boiler must be cleaned on a regular basis to avoid scale buildup and to increase the boiler’s lifespan.
As we’ve seen, the efficiency of the hot water system can actually be affected by the potential presence of limescale in the boiler.
Limescale in the boiler can be prevented and combated in a number of ways. Here are some recommendations:
• Put in a water softener: Prior to the water entering the boiler, a water softener can lower the levels of calcium and magnesium in the water. Scale deposits can be prevented in this way.

• Use anti-scaling products: To stop scale deposits from forming, certain products can be added to boiler water. Usually, sulfuric or citric acid is the base for these products.
• Conduct routine boiler cleaning: In mixed boilers, routine boiler cleaning, sometimes once a year, can eliminate scale deposits that have already developed and stop additional buildup in the plate exchanger.
• Fit a filter: a filter can help catch waterborne scale particles before they get into the boiler.

• Keep an eye on the water’s “hardness” level; if you know it, you can take certain precautions to avoid scale buildup. The levels of calcium and magnesium in the water can be determined using water hardness test kits.
In any event, it’s crucial to maintain your boiler according to the manufacturer’s instructions and to seek advice from a qualified technician if you have any questions or concerns.

Considerations Before Boiler Descaling

When descaling a boiler, there are numerous considerations to make. Before beginning the actual descaling process, the following questions should assist you in obtaining the necessary data.

• Which boiler type and design low-temperature hot water, high-temperature hot water, low-pressure steam, or high-pressure steam is it?

• The boiler’s size can be found on the nameplate or in other records.

• What is the purpose of the boiler? Process (heat exchanger) or heating?

• How old is the boiler?

• The features and analysis of the deposits.

• Is the thickness of the deposit average, thickest, or thinnest?

• When was the last time you cleaned, if at all?

• Has any boiler feed-water treatment been implemented?

• History of boilers?

• What is the water capacity of the boiler?

• The cleaning solvent’s compatibility with the system’s metallurgy.

• The cleaning application is simple.

• The process for disposing of spent solvents.

• The cost of the cleaning technique.

• Are there any sections or tubes leaking right now? If so, they ought to be fixed prior to cleaning.

The Fundamentals of Boiler Descaling

Note: The steps listed below are merely meant to serve as a guide. Since each boiler is unique, some steps that are not on the general procedure list below might be necessary.
1. Turn off the boiler.
2. While maintaining pressure, blow down the unit.
3. Empty the unit and flush it.
4. Shut off the steam valve.
5. Add the descaler and adhere to any instructions given by the manufacturer.
6. Move back to a vented container via the boiler’s high point or pressure relief valve after passing through the drain or low point.
7. Depending on volume, circulate for 4–8 hours.
8. Let the steam valve open.
9. Empty, flush, refuel, and turn on.

Certain descalers might need extra steps that aren’t mentioned. If you require professional assistance, don’t hesitate to contact the descaler’s manufacturer.

How Frequently Should a Boiler Be Descaled?

The frequency of boiler cleanings is recommended by published standards published by boiler manufacturers, industrial cleaning companies, and industry associations. The majority of standards determine when a boiler needs to be chemically cleaned based on the deposit weight density from a tube sample. When comparing outcomes over time, you should make sure that a consistent methodology is applied.

Certain boilers can withstand a lot of misuse and neglect and still perform competently. To make it simple to view and clean the tubes, they might even have hinged and davitated doors. Tube sampling, visual inspection, or other techniques should be used to keep an eye on the deposits, regardless of the kind and design of your boiler.

Solution for Commercial Boiler Descaling

Six industrial descalers that are perfect for use on commercial boilers are available from us:
• Dynamic Descaler: The best descaling product available with the least amount of corrosion.
• Platinum Descaler: Suggested for use on commercial boilers made of stainless steel.
• Aqua Safe Descaler: A descaling solution for industrial boilers that is approved for use with potable water.

• Descale 518: Also advised for use on commercial boilers made of stainless steel.

• Citric Descaler: Compared to other descalers on the market, this one dissolves nearly twice as much calcium carbonate. Our citric descaler is environmentally friendly.
• Aluminum Descaler: A special descaling agent that doesn’t affect cast molding or the aluminum dyes 7075 and 6061.

Conclusion

Boiler descaling is an essential necessity for guaranteeing peak performance, energy economy, and equipment longevity; it is not merely a routine maintenance procedure. Scale buildup impairs heat transfer, raises operating expenses, and increases the chance of mechanical failure. Customized descaling procedures are crucial because every boiler type, including combi, condensing, electric, steam, fire-tube, and water-tube boilers, has distinct vulnerabilities to scale buildup. Facility managers and technicians can protect their systems by identifying the causes of scale, putting preventative measures like water treatment and filtration into place, and selecting the best descaling technique. For all boiler applications, regular descaling eventually results in safer operation, less energy use, and less downtime.

To explore the latest innovations in water and energy technologies, and discover a wide range of products and solutions from around the world, you can visit the virtual exhibition AQUA ENERGY EXPO which featuring leading companies in water treatment, desalination, and sustainable energy through the following link:
https://aquaenergyexpo.com/