In any heating network, there are foreign particles circulating together with water through pipes and radiators. This is rust, salt residue from the boiler (scale), all kinds of solid impurities. If the amount of debris is large, heat exchangers begin to clog, and mud deposits form in the batteries and pipelines. They interfere with the flow of coolant and normal heat transfer. The solution to the problem is flushing the heating system of a private house, which you can do it yourself.
When is the heating flushed?
Immediately, we note that individual heating systems of apartments and country houses very rarely need washing. Generally, a deterioration in heating is due to other causes, such as airing. Let us explain:
- You filled the network with fresh water or antifreeze, drove the air out, started the boiler.
- The coolant “burns in” for 2–3 weeks - a salt precipitate forms in the heat exchanger, solid particles are trapped by a strainer. During this period, the sump needs to be cleaned frequently.
- Since the amount of impurities in the network water is limited, precipitation soon ceases. Heat exchangers, pipes and batteries simply have nothing to clog.
That is, a closed system can work without any cleaning. If it is constantly fed from the water supply network, the amount of salt sediment will increase indefinitely. Over the years, pipelines will “half-grow” by half, silt will settle in radiators.
A similar effect occurs due to the penetration of oxygen into the coolant. Air bubbles cause corrosion of metal pipes and fittings from the inside, particles of iron oxide (rust) are formed, they are constantly found in the sump. The cause may be poor-quality plastic pipes without a protective oxygen barrier.
Reference. The "accustomed" coolant often acquires a dark or even black color, this is quite normal. The brown color of the water indicates a large amount of rust.
So, in what cases is the heating flushed:
- Ceased heating appliances - one or more. Battery sections warm up unevenly, the bottom remains cold. At the same time, you eliminated all possible malfunctions, but did not receive a result.
- For various reasons, you are constantly replenishing the system with fresh coolant. For example, for the operation of electrode boilers, you need water with a certain amount of salts that decompose in the course of a chemical reaction. It is necessary to salt the coolant or fill in a new one.
- Oxygen enters the mains water, the filter is often clogged (almost daily), the radiators do not heat well, the boiler works at maximum speed.
The conclusion is simple: flushing is done on the fact of malfunctions of the water heating system, no periodicity must be observed. There is another approach to the centralized heat supply of apartment buildings, where the radiator network is washed annually, after which pressure testing is performed (according to the requirements of SNiP).
How to flush the system - 3 available methods
Without the use of specialized equipment, you can flush in the following ways:
- local cleaning of radiators;
- simple flushing of pipes and heating appliances with tap water;
- chemical (otherwise - hydrochemical) cleaning of heating pipelines.
Reference. Centralized heating networks of apartment buildings are washed hydropneumatically. A powerful compressor is connected to the elevator unit located in the heat point.A mixture of water and air is pumped through the batteries and pipes of all apartments, tearing off particles of solid deposits, and even more so silt. Then the dirt is discharged into the sewer.
Most homeowners do not have compressor installations. In addition, you will need a mixing chamber and experience in carrying out such activities, otherwise you run the risk of violating the tightness of the joints. This means that the hydropneumatic method is of little use for self-flushing the system. We recommend starting with a clean dead battery.
Radiator cleaning
It is quite simple to identify a problematic battery - when the heating is running, touch the entire surface with your hand or measure the temperature at different points with a contact / non-contact thermometer, and then compare it with the temperature of the supply line. If sections warm up unevenly, flush the radiator.
In an apartment with central heating, washing the battery is done as follows:
- We block the shut-off valves on the inlets to the heater. We unscrew the upper plug with a Mayevsky tap with a gas key, substitute the basin, drain part of the coolant.
- Carefully open the tap on the supply eyeliner so that debris is thrown out of the radiator by the pressure of water. Of course, keep the basin under the stream. When the light coolant goes, we close the valve, put the cork in place.
- Similarly, repeat the above manipulations with the bottom plug. After washing, we twist the cork, open both taps, bleed the air.
The described technology is applicable in private homes with automatic recharge of heating from the water supply. Only before flushing is it better to close the valves at the boiler and expansion tank. In other cases, you need to remove the radiator and wash separately. Connecting a hose to the heating network from a cold water supply is a risky option, when water is supplied “to a closed valve”, a high pressure of 3 ... 6 Bar can violate the tightness of the system.
Disconnecting the battery gives 1 plus - the ability to look inside the supply pipes. Having seen deposits there, covering 1/3 or half of the bore, it is easy to decide on the further flushing of all heating pipelines.
Note. In an open system, we have an expansion tank in communication with the atmosphere. If it is not possible to cut off the container with a tap, then rinsing the battery through recharge will not work, water will trample through the top and begin to heat the house.
Cast iron radiators that have served more than 10 years will definitely have to be removed and cleaned with some chemistry, for example, caustic soda solution (see video below). The precipitate at the bottom of each section rarely remains liquid; it is unlikely to be able to remove it with running water.
Rinse with running water
The essence of the method is to remove dirt from the system using a large flow of water from the centralized water supply network. Immediately, we note the disadvantage of this option: only liquid sludge and suspended particles traveling with the coolant can be washed out of pipes and heating devices. If the batteries have solid deposits, then removing them will not work.
How is such a hydraulic flushing performed:
- We connect the water supply hose to the feed fitting. As you know, this pipe is cut into the lower point of the return heating line. The drain hose is connected to the gap of the supply line (for example, instead of the circulation pump or at the junction of the crane) and put into the sewer or to the area near the house.
- We clean the sump, open all the radiator taps and balancing valves.
- The boiler must be cut off from the system using taps, it must be washed separately. It is not necessary to drive away all the dirt through its heat exchangers, especially for double-circuit heat generators.
- We open the water valve, gradually increasing the flow of water. As you understand, backwashing begins, that is, the flow moves towards the flow of the coolant in the operating mode.
- When the stream from the drain hose becomes transparent, we block the water, swap the hoses and flush the heating in the other direction - along the movement of the coolant.
- Upon completion of the hydraulic cleaning, we again fill the system, start the boiler, check the operation of the batteries and do the balancing.
An important nuance. It should be understood that flushing is carried out due to the large flow of water through the heating pipes, and not due to strong pressure. Do not supply water “to the closed valve”, only through the open drain hose. The heating network is not designed for water pressure.
An open tank system must first be prepared for continuous flushing. There are 2 options: cut off the expansion tank with a tap or plug the overflow tube. The second method is suitable for tanks without a top cover. If this is not done, the water will overflow the tank and flow out, and the portion of the system after it will remain unwashed.
Chemical Cleaning Option
This is the most affordable way to thoroughly flush the heating system with your own hands. To implement it, you will need:
- submersible vibration pump, household series, for example, "Trickle" (or similar);
- water filter in the form of a flask with 2-3 replaceable cartridges;
- a special tool for washing heating networks and radiators;
- tank for chemical solution;
- connecting fittings.
The procedure is performed in 3 stages - preliminary removal of contaminants with running water, then the chemical cleaning itself, at the end - final washing. The first and third stages are done according to the technology described above using a water supply system; in the second, a submersible pump and a filter are used.
How to flush the heating system chemically (stage 2):
- Prepare a washing solution in a barrel, following the instructions on the packaging. The amount of liquid corresponds to the volume of the coolant in the heating network plus the capacity itself. How to choose a suitable chemical agent, we wrote at the end of the article.
- Connect the pressure port of the pump to the heating supply, immerse the device in the barrel. The filter is placed on the drain line, which is sent to the same container, as shown below in the video.
- Remove the mesh from the standard sump, wrap the empty cork back. Otherwise, you will have to clean it every 10 minutes.
- Turn on the pump, pump the reagent into the system. Make sure that the solution flows into the barrel from the drain hose and that there are no leaks.
- Flush the heating system until the water stream is lighter. Heavily contaminated filter cartridges must be replaced during cleaning.
- Wash the remaining chemistry from the radiator network with running water (stage 3).
Reminder. Chemical flushing should only affect pipes, radiators and underfloor heating (if necessary). It is not recommended to pump reagent through the boiler; it is better to clean the unit separately. An open expansion tank should be cut off from the pipeline network or sealed.
How to flush heating
In the distribution network, you can purchase various reagents, offered in 3 types:
- liquid concentrate;
- powder;
- ready solution.
The concentrate and powder must be diluted with water, following the manufacturer's instructions. As a rule, before cooking, the water is heated to 40 ... 60 ° C. Ready-made liquid for flushing the heating system is poured into the barrel, after use it is disposed of.
We give a number of recommendations on how to better rinse the heating pipes:
- The active ingredients of the reagent should not damage the elements of your system, for example, interact with aluminum radiators. Choose chemistry based on the materials from which metal parts and fittings are made.
- It is better to buy flushing with various useful additives - corrosion inhibitors, biodegradable additives.
- The composition of the reagents is divided into 2 groups - acid and alkaline.The former act faster, but are considered more aggressive in relation to equipment and hazardous to health. It is better to choose an alkaline concentrate.
We do not recommend using various folk remedies for washing, in particular citric acid. Firstly, it is effective only against scale, which is found only in boiler heat exchangers. Secondly, a high concentration of an acid solution is necessary, with a large amount of water it cannot be provided.
Note. Factory-made reagents are allowed to be drained into the general sewage system; no additional treatment is required.
Conclusion
So, it is quite possible to do the washing of heating in a private house on your own. But first, it’s important to understand one thing - is this operation necessary at all. If the coolant in the district heating network is really capable of clogging the battery, then in a closed system there is no such problem. Carefully check the radiators for air jams before proceeding with a partial or full flush.