Do-it-yourself methods for flushing the boiler heat exchanger

Autonomous heating is installed in many apartments and most private houses with their own water supply. This system is not designed to run forever without maintenance or preventive measures. The water circulating along the circuit is not perfectly clean. In the process of heating in the range of 45-75 degrees, limescale forms in the pipes, soot collects outside. This negatively affects the efficiency of the equipment and leads to many undesirable phenomena. To prevent this, the boiler heat exchanger is cleaned. It is better to perform this procedure with your own hands, since the services of a master will cost a round sum. The tubing should be cleaned regularly as it becomes dirty.

The need for cleaning

High-quality flushing of the gas boiler heat exchanger is the key to its long-term and trouble-free operation throughout the entire heating season. Faced during this period with the need to turn off the heat and emergency repairs is not the best prospect that a property owner wants to face.

If you do not clean the heat exchangers within the time recommended by the manufacturer, the following problems are likely to occur:

• Overheating of equipment. It occurs due to the low speed of movement of water, which receives more energy than is required by the instructions.
• Break the contour. Occurs due to the transformation of liquid into steam when stationary due to clogged channels.
  
• Breakdown of the circulation pump. The unit overheats, since its power does not find a way out due to the impossibility of free flowing water.
• Increased noise. It occurs due to the swirling of the liquid and the formation of air bubbles when the boiling process begins in the tubes.
• Increase in gas consumption. To heat a room to the desired temperature, you need to consume 1.5-2 times more energy.
• Decreased productivity. This is due to the accumulated soot on the tubes, which acts as a heat insulator. As a result, the double-circuit boiler produces water 10-15 degrees colder than the set parameters.

Timely flushing of the heat exchangers will avoid such complications. If they do occur, it is necessary to immediately stop the system, drain the water from it and clean the internal circuits.

Heat exchanger flushing frequency

The frequency of cleaning the heat exchangers is prescribed in the operating instructions attached to the product. Most manufacturers recommend doing this every 2 years. However, if water saturated with lime is used, a thick layer of plaque can boil already in one heating season, even if there is a stainless steel circuit in the boiler. When a filtration system is installed in the harness, the procedure can be carried out at intervals of 4-5 years. Water needs to be changed annually, as it changes its structure and acquires properties that are aggressive towards metal.

It is best to calculate the required frequency of cleaning the heat exchanger empirically. After the end of the heating season, you need to disassemble the boiler, remove the circuit and assess its condition. The plaque will tell you how long it will take for its thickness to reach a critical state.

Cleaning methods

It is recommended to rinse the boiler heat exchanger immediately after the end of the heating season, when the plaque has not had time to gain strength. To complete this procedure, one of the available methods is selected, which is most suitable for the owner of the property.

There are such options for cleaning water circuits:

• Manual (mechanical). A simple and inexpensive way to get rid of scale and carbon deposits. The work uses improvised devices that can be found in every home. From the outside, the soot is scraped off with a knife or wire brush. Internal deposits are removed with a steel cable, one end of which is untwisted and made in the form of a brush. These cables are used in bicycle braking systems and gas regulation in motorcycle equipment. After rough cleaning, which removes most of the dirt, the product is re-processed. It involves soaking the tubes in any reagent that dissolves limescale and is safe for the metal. The processing time is 20-25 minutes, depending on the concentration of the substance. The hotter it is, the better the effect will be achieved.
• Chemical. Flushing of the plate heat exchanger is carried out with household chemicals or self-preparation means. The advantage of this method is that the cleaning procedure can be performed without dismantling the tubes if a flushing pump for heat exchangers is available. If this device is not yet available, the primary and secondary circuits are immersed in an acidic solution, which is heated to a temperature of 40-60 degrees. Heating promotes more activation of the chemicals. An acid resistant reservoir must be used to avoid damaging the reagent. The soaking time is determined experimentally, by analyzing the state of exfoliation or dissolution of plaque. In a weak solution, the parts are boiled over low heat. A good effect is given by the Laval product of Minsk production.
• Hydrodynamic. A pump is used to flush the heating system. Abrasive additives are added to the water; under a pressure of up to 2 bar, the station drives it through the system. The filter is preliminarily removed to ensure the unimpeded movement of the liquid. During flushing, the pumping direction must be changed several times in order to better clean the channels. The cleaning effect is achieved by the rapid flow of liquid and its friction against the inner walls of the tubes. Using this method, they can be restored to their original state.

You need to clean the contours carefully, without applying excessive force or applying pressure above the calculated one. Despite the fact that high-quality steel is used in the manufacture of heat exchangers, the products can be easily damaged.

Flushing fluids

A wide variety of chemicals are available in hardware stores in the form of liquids, gels and powders. Almost all of them are acid-based. Most often, adipic, citric and sulfamic acids are used as a reagent.

The following brands have proven themselves best:

• Alfa;
• Baxi;
• Cip;
• Eliminate;
• Laval;
• Pump;
• Steeltex
• VV;
• Aquaprof;
• Alf.

Before buying, you should study the scope and conditions of use of the product, recommended brands of boilers, application rules and warnings.

Washing machines

The designers have developed special devices so that the heat exchanger can be cleaned without removing it from the boiler body. The machine is connected to the nozzles, after which it begins to drive the reagent saturated with abrasive along the circuit. In this case, an increased pressure is created inside the tubes, and the temperature of the liquid rises to 60 degrees. The most popular are household appliances of the Ariston and Beretta models. The products are distinguished by their compactness and high performance. They can easily find a place in the closet or closet.

It makes sense to purchase such equipment only if cleaning must be carried out annually, since the estimate for the booster and reagents can reach 38-60 thousand rubles. But the services of professionals will also cost a lot. In large megalopolises they cost 3-7 thousand rubles, and in the regions 2-4.5 thousand rubles. If you clean the boiler every year, the payback will begin in 6-10 years. Buying a booster is expensive, but you can reduce costs and even make a profit if you rent out the unit or provide services to neighbors and friends yourself for a reasonable fee. It is enough to rinse the heat exchanger yourself once to acquire the necessary skills. Since all boilers have almost the same device, there will be no problems with servicing other models.

Instructions for flushing the heat exchanger with your own hands and at home

Before servicing the heating boiler, it is necessary to release the coolant from the system, shut off the water and gas supply, and disconnect it from the electricity.

To work, you will need the following property:

• screwdriver;
• indicator;
• pliers, pliers;
• paint brush, scraper;
• metal brush, thin cable with a brush, toothbrush;
• goggles, rubber gloves;
• a container of appropriate size and volume;
• rags.

Cleaning the water circuits must be carried out in the following sequence:

1. Remove the cover that covers the internal components. Take out the casing and thermal insulation.
2. Disconnect the wires from the gas valve, remove the thermocouple;
3. Drain the water from the boiler. For this, a drain valve is used, located at the bottom of the housing.
4. Remove the fuel supply pipe;
5. Unscrew the screws from the burner, remove the assembly and place it on a wide, stable base.
6. Cover the electronic and switching units with cellophane in order to prevent water ingress on them.
7. Scrape off the dirt from the outside of the device with a metal toothbrush or knife. Clean the igniter, flame sensor and automatic ignition one after the other.
8. Get the secondary circuit, carry out similar actions with it.
9. Carry out the primary mechanical cleaning of the internal channels with a cable with a brush.
10. Stir the citric acid solution. It is taken 200 g per 10 liters of water.
11. Put the vessel on the stove, immerse the heat exchangers in it, turn on the heating. Bring the solution to a boil and soak for up to 30 minutes.
12. Take out the parts and wait for them to cool. Visually check the quality of the achieved result. If plaque remains, remove it with a brush or re-boil.
13. After cleaning the heat exchangers, rinse them several times with clean water to rinse off all reagents.
14. Assemble the unit, observing the sequence in which the parts are installed.

With a booster, everything is much simpler. You just need to fill the device with a reagent, connect it to the pipes and turn it on. At the end of the rinse, the solution is poured out and replaced with clean rinse water.