Heating System Cleaning for Old Systems
Cleaning the heating system with an external pump is a fundamental procedure to ensure the proper functioning of the system, maintain energy efficiency, and extend the life of the boiler and the radiators. In this comprehensive guide, we will explore the importance of this practice, the detailed procedure, and the advantages of using an external pump.
Why Cleaning with an External Pump is Necessary?
Over time, the heating system accumulates impurities such as lime scale, rust, sludge, and other sediments that compromise its functionality. This results in:
- Reduced energy efficiency: Deposits decrease the heat transfer capacity, increasing consumption and bills. Additionally, many radiator valves, especially if they are thermostatic, tend to get clogged with dirt, compromising heat balance. The three-way boiler valve is particularly prone to breaking due to the buildup of impurities and excess sediments.
- Increased wear and tear: Corrosion and scaling damage pipes, radiators, and the boiler. Furthermore, circulating dirt corrodes the boiler metals, causing visible damage even on new condensing appliances if installed without proper system cleaning. In such cases, it is common to observe perforations in the primary heat exchanger made of stainless steel, where limited water flow due to impurities causes localized overheating and subsequent breakage.
- Risk of malfunctions: Blockages and restrictions in the pipes can prevent the proper circulation of water.
A dirty system often exhibits obvious symptoms:
- Radiators with cold spots; cold areas can affect the radiator both horizontally, when only the first sections heat up and not the rest, and vertically, when the upper part is very hot while the lower part remains practically cold. This phenomenon is often caused by the buildup of dirt, sludge, or trapped air, which obstructs the proper circulation of water.
- Noisy boiler due to sediments; in boilers with an atmospheric burner, it is common that, after years of operation, sediments obstruct the primary heat exchanger. This component is particularly delicate as its plate represents a real “bottleneck” for water flow. When the exchanger becomes clogged, circulation is drastically reduced, causing localized overheating. This phenomenon not only makes the boiler noisier but also increases the risk of severe malfunctions and efficiency losses.
- Frequent need to bleed radiators;
- High consumption and poor thermal performance.
Traditional methods such as manual bleeding only solve problems related to trapped air but do not address the root causes. Cleaning the heating system with an external pump thoroughly removes all sediments, restoring the original efficiency of the system.
Detailed Procedure for Cleaning with an External Pump
Here are the main steps of the cleaning process:
How to Perform Heating System Cleaning with an External Pump. Step-by-Step Complete Procedure: From System Preparation to Final Cleaning Verification
1. System Preparation
Isolate the boiler by closing the supply and return valves to prevent the chemical product from damaging the boiler components. In the case of using the external pump, it is necessary to disconnect the boiler from the system and connect the pump directly to the supply and return of the system. This allows for a complete and effective cleaning without risks to the boiler.
2. Initial Rinse
A first rinse with clean water removes superficial dirt and prepares the system for chemical cleaning. Recommended Duration: At least 15 minutes.
3. Introduction of the Cleaning Product
Use a specific product for the type of system:
- Termo Cleaner 40 for radiant systems;
- Cillit HS 23R Plus for cast iron radiators or iron pipes.
The dosage depends on the water volume and the presence of the external pump.
Microconductivity Meter: A fundamental tool to monitor the concentration of the chemical product during heating system cleaning. It measures the water’s conductivity, indicating the amount of dissolved substances present, such as mineral salts and chemical residue. During the process, the microconductivity meter helps control the proper dilution of the detergent and verifies when the water has reached optimal conductivity, signaling that the cleaning is effective and the system has been adequately rinsed. This tool is particularly useful to ensure no chemical residues remain within the system, preventing potential future damage or corrosion.
- Termo Cleaner 40 for radiant systems;
- Cillit HS 23R Plus for cast iron radiators or iron pipes.
4. Forced Circulation with External Pump
The external pump distributes the product at high circulation, reaching even the most difficult areas. Duration: 1 to 2 hours with flow reversal every 15 minutes to optimize cleaning.
5. Drainage of Dirty Water
Drain the system until the water flows completely clear. Proceed from the last radiator to the first.
6. Final Rinse
Rinse with clean water to remove any residue of the cleaning product.
7. Verification of Cleaning
Turbidimeter: An essential tool to check the clarity of the system’s water. The turbidimeter measures turbidity, i.e., the presence of suspended particles in the water, providing a clear indication of the cleanliness level achieved after cleaning. Water with low turbidity indicates a clean and properly functioning system. This check is crucial to verify the effectiveness of the cleaning and prevent future accumulation of impurities in system components.
Infrared Thermometer: A versatile and indispensable tool to verify the absence of cold spots in radiators. This device quickly and accurately measures the surface temperature of radiators, highlighting any thermal inconsistencies. Cold spots may indicate air accumulation, dirt deposits, or poor water circulation in the system. Using an infrared thermometer allows for the identification of these issues and confirms the effectiveness of the external pump cleaning, ensuring uniform heat restoration across all radiator surfaces.
Why the External Pump is Crucial?
The external pump is the key tool for effective cleaning: it is indispensable because it integrates all the necessary equipment for a complete and precise operation.
- Controlled Drainage: The pump facilitates the effective drainage of dirty water, ensuring that all impurities are removed from the system.
- Flow Reversal: It allows reversing the water flow during cleaning, a crucial operation for removing even the most stubborn sediments in the most difficult-to-reach areas.
- Loading of Clean Water: The external pump allows the rapid reintroduction of clean water, ensuring a complete rinse.
- Higher Power: Thanks to sufficient horsepower, the external pump is able to thoroughly clean the entire system, unlike the boiler’s simple circulator which has limited power and is not designed to handle intensive cleaning.
These features make the external pump the ideal tool to ensure a thorough and professional cleaning of the heating system.
Chemical Products and Safety
- Modern products are biodegradable and safe, but must be handled with caution:
- Use protective gloves and goggles;
- Ensure adequate ventilation of the area;
- Dispose of washing water in accordance with regulations.
The choice of product must take into account the type of system (pipe material, type of radiators).
Maintenance and Additional Checks
After washing, it is important to monitor the system for possible pressure drops, which could indicate leaks or settling due to the removal of sediments. This monitoring is recommended for at least a short period to ensure that everything is functioning correctly.
Additionally, it is advisable to perform:
- Check the air bleed valves to eliminate trapped air;
- Boiler maintenance to ensure efficient operation;
- System balancing for an even distribution of heat. During cleaning, the installation of thermostatic valves is also recommended, which allow automatic balancing and regulation of water flow in each radiator. This intervention ensures optimal heat management in each room, improving living comfort and contributing to further energy savings.
- Check the air bleed valves to eliminate trapped air;
- Boiler maintenance to ensure efficient operation;
- System balancing for an even distribution of heat. During cleaning, the installation of thermostatic valves is also recommended, which allow automatic balancing and regulation of water flow in each radiator. This intervention ensures optimal heat management in each room, improving living comfort and contributing to further energy savings.
Conclusion: Efficiency and Savings with a Professional Cleaning
Cleaning the heating system with an external pump is an essential intervention to maintain energy efficiency and prolong the life of the system. By deeply removing lime scale, rust, and sediments, this procedure allows to:
- Reduce energy consumption;
- Avoid costly failures;
- Improve thermal comfort.
For optimal results and to avoid risks, it is advisable to rely on an experienced professional.
Frequently Asked Questions about Heating System Cleaning
It is a deep cleaning procedure that uses an external pump to remove lime scale, rust, and sludge accumulated in the heating system.
Cleaning removes impurities that compromise energy efficiency, reduce thermal performance, and cause failures in radiators and boilers.
Generally every 10-12 years, but the frequency may vary depending on water hardness and the type of system.
Radiators with cold spots.
Noisy boiler.
High energy consumption.
The external pump ensures a deeper cleaning thanks to forced circulation and flow reversal, which are impossible with manual methods or zero discharge. However, it is more expensive.
Specific products such as Termo Cleaner 40 for radiant systems and Cillit HS 23R Plus for cast iron radiators or iron pipes are used.
Yes, if performed correctly with appropriate tools and compatible products. It is essential to isolate the boiler and monitor the process.
The complete procedure can last from 2 to 4 hours, depending on the size of the system and the level of dirtiness.
Yes, by removing sediments and improving water circulation, energy consumption is reduced, and heating efficiency is optimized.