how to set temperature and flow during descaling

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Boiler system decalcification is a critical process that requires precise temperature and flow rate settings to effectively remove deposits without damaging the pipe material or heat exchangers. The correct combination of these two parameters determines whether the lime scale is released in time or if inefficient cleaning and unnecessary pump wear occur.

Critical temperature parameters for different types of deposits

The solution temperature is the primary factor that accelerates the chemical reaction of dissolving lime scale, but increasing it above 60 °C can lead to the formation of new deposits or damage to boiler seals. For standard system decalcification, a temperature of around 45 to 50 °C is sufficient, while hard, old deposits require a threshold of 55 to 60 °C, with higher temperatures being risky even for modern low-energy boilers.

We have recorded a case in practice where a technician increased the temperature to 70 °C in an attempt to quickly clean an old panel radiator, which caused the immediate formation of a new, hard deposit at the highest temperature point, worsening the problem. Therefore, it is essential to adhere to the maximum temperature recommended by the boiler manufacturer and to use a high-quality pump with the ability to regulate performance, such as models from the KAMMAK range designed for professional applications.

Optimization of flow for maximum efficiency

The flow rate must be sufficiently high to flush away the released lime scale particles, but at the same time not too high to avoid mechanical damage to the inner walls of the pipes or exceeding the allowed pressure in the system. The ideal flow rate ranges from 4 to 6 liters per minute for standard home heating and up to 10 liters per minute for industrial heat exchangers, with a constant flow rate throughout the entire process being important.

Low flow below 3 l/min causes the released lime scale to settle back in other parts of the system.
Increased flow above 8 l/min can cause erosion of copper pipes and damage to valve seals.
Regular pressure checks on the manometer help maintain optimal flow regardless of filter contamination.
For large floor heating systems, it is necessary to gradually increase the flow to prevent surge peaks.

One of the common mistakes is ignoring the pipe resistance when setting the pump; if the system is very long and has many bends, the pump performance should be reduced to avoid motor overload and loss of flow due to local blockages.

Mutual feedback between temperature and flow in real time

Temperature and flow are interrelated parameters that must be controlled synchronously, as an increase in temperature reduces the water viscosity and thus changes the hydraulic properties of the system, which requires an adjustment of the flow rate. If you increase the solution temperature by 10 degrees, you should expect a natural increase in flow of approximately 5 %, so it is necessary to compensate for this by regulating the pump or valves.

In technical practice, the method of gradually increasing the temperature by 5 degrees every 15 minutes and simultaneously adjusting the flow to remain within the target range has proven effective, allowing for efficient separation of deposits without transferring them to other parts of the system.

Process steps for setting parameters

Successful decalcification begins with system preparation, which includes measuring the current temperature and pressure, connecting the pump, and setting the initial parameters according to the boiler type and deposit condition. The first step is always to set low values (temperature 40 °C, flow 3 l/min) and gradually increase them only if the system reaction proceeds smoothly without warnings.

Measure the initial pressure and temperature in the system and compare them with the boiler manufacturer's manual.
Set the pump to minimum performance and start circulation of cold water to purge air.
Gradually add the solution and increase the temperature to 45 °C, monitoring the reaction on the manometer.
If the pressure stabilizes, increase the temperature to 55 °C and adjust the flow to 5-6 l/min.
Maintain these parameters for 30-45 minutes and monitor the purity of the discharged water.

It is important not to forget about safety features such as pressure-reducing valves and expansion vessels, which can be affected by pressure and temperature changes during the process, so it is necessary to keep the overall system condition under control at all times.

Common errors and risks with incorrect settings

Incorrect parameter settings lead not only to inefficient cleaning but also to serious damage, such as corrosion of metal parts due to an overly aggressive solution or mechanical cracking of heat exchangers due to surge pressures. One of the most common errors is ignoring the temperature limits of plastic pipes, which can deform at temperatures above 60 °C, leading to leaks and seepage.

Another risk is using too high a flow rate at low temperatures, which causes the chemical solution to not react with the deposits and simply transfer them further in the system, where they settle in a narrower area and create a complete blockage. In such cases, it is often necessary to disassemble part of the pipe and clean it manually, which increases costs and the time schedule for the work.

Diagnosis and maintenance of pumps during the process

During the actual decalcification process, it is necessary to regularly check the condition of the pump, motor temperature, and oil level, as increased load and temperature can cause overheating and premature bearing wear. Modern KAMMAK pumps have built-in protective elements, but their functionality depends on correct parameter settings and regular maintenance, which should be carried out by an experienced technician.

Technicians should have a thermometer and pressure gauge ready to measure the temperature and pressure in the system, so they can react promptly to any abnormalities and stop the process before damage occurs. Pump maintenance after the season is just as important as the descaling process itself, as proper storage and flushing prevent corrosion and extend the machine's lifespan.

Hydraulic diagram for circulation descaling

This diagram illustrates the ideal flow of the solution through the heat exchanger in order to maximize contact with deposits and prevent the formation of "dead zones" where limescale could settle again.

Frequently Asked Questions

How long does the descaling process take with optimal parameters?

The process usually lasts between 45 to 90 minutes, depending on the thickness of the deposits and the type of chemical solution used.

Can I use regular water instead of a special solution?

Ordinary water is not sufficient for effectively removing limescale, so the application of specialized acids or enzymatic solutions is necessary.

What should I do if the pump starts to overheat?

Immediately reduce the temperature and flow of the solution, check the condition of the cooling system, and if necessary, stop the process.

Proper setting of temperature and flow is key to a successful and safe descaling process, which ensures the long-term functionality of your heating system and prevents costly repairs. Adhering to these guidelines will allow you to achieve maximum efficiency with minimal risk of damaging equipment and piping.

Do you have a question about this topic?

Not sure or dealing with a specific situation in your home? Write to us – we are happy to help.