Answers to scaling issues of Ferroli gas wall-hung boilers
The primary concern with gas wall-hung boilers is the scale buildup inside, which includes calcium and magnesium compounds such as calcium sulfate, magnesium sulfate, and calcium carbonate. The amount of these substances in wall-hung boilers is minimal. During heating, if floor heating is used, the water temperature should not exceed 60°C, while the general scaling temperature of water is 67.5°C, so no scaling will occur. If radiators are used for heat dissipation, the water temperature is required to be around 80°C, which has already exceeded the scaling temperature, leading to scaling. In the radiator system, as long as there is no leakage, the water volume remains fixed, and the calcium content is also a fixed quantity. This water continuously goes through cycles of being heated - releasing heat - reheated - releasing heat again. Once it reaches the scaling temperature, no further scaling will occur. There's no need to worry about domestic hot water since the domestic hot water temperature of the wall-hung boiler generally does not exceed 60°C.
Based on years of after-sales service experience with wall-hung boilers, they can indeed become blocked due to scale buildup in the heat exchanger, causing reduced water flow, greatly decreasing heat exchange efficiency, and even leading to dry burning and automatic shutdown. What causes this?
This is actually not the scale we refer to but impurities in the water. Although there is usually a filter at the water inlet of the wall-hung boiler, some small impurities cannot be filtered out. Over time, these impurities block the heat exchanger pipes. This phenomenon is common in some original imported models because most of these imported models use plate-type heat exchangers, which have small gaps and low flow rates, making them prone to blockage. Therefore, currently, most wall-hung boilers used domestically are equipped with tube-type heat exchangers.
Moreover, the heating part of the wall-hung boiler's pipeline is the least likely to accumulate scale because it is a closed system with few calcified substances and impurities. The biggest problem for wall-hung boilers is that the domestic hot water pipeline is the most prone to blockage. Since domestic hot water involves continuous injection - heating - flowing out, large amounts of impurities adhere to the pipelines, causing so-called scaling. Such scale cannot be cleaned with acidic solutions, as not only would it fail to achieve the desired effect, but it could also corrode the internal pipelines, shortening the lifespan of the wall-hung boiler. A reminder to all users: Some descaling agents sold on the market specifically for wall-hung boilers overly emphasize the scaling issue of wall-hung boilers. In reality, they don't have much effect. Furthermore, there are currently no targeted or effective solutions for the impurities and dirt attached inside the wall-hung boiler.
Source: Beijing Ferroli Wall-Hung Boiler Repair http://blog.sina.com.cn/faluolibigualu