Normal pressure in a closed heating system is very important. Firstly, this is a warm room in winter, and secondly, the normal operation of all components of the boiler. But far from always the arrow is in the range we need, and there can be a lot of reasons for this. High and low pressure in the heating system leads to blocking of the pump and the absence of warm batteries. Let's talk in more detail about how many atmospheres should be in our pipes and how to fix common problems.
Some general information
Even at the design stage of the heating system, pressure gauges are installed in different places. This is necessary in order to control the pressure. When the device detects a deviation from the norm, it is necessary to take some action, a little later weLet's talk about what to do in a particular situation. If no measures are taken, the heating efficiency drops, and the life of the same boiler is reduced. Many people know that the most detrimental effect on closed systems is exerted by water hammer, for which expansion tanks are provided for damping. So, before each heating season, it is advisable to check the system for weaknesses. This is done quite simply. We need to create excess pressure and see where it shows up.
Low and high pressure in the system
Often the pressure drop in the heating system is due to several factors. Firstly, this is a coolant leak, which is the most common reason for a decrease in the number of atmospheres. Leakage is most often located at the junction of parts. If it is not there, then most likely the problem is in the pump. Scale in the heat exchanger is another reason for lowering the pressure in the system. The same applies to the physical wear of the heating element. But the increase in pressure happens due to the formation of an air lock. Also, the reason may be the difficult movement of the carrier through the pipes due to obstruction in the filter or sump. Sometimes, due to automation failures, excessive replenishment of the system occurs, in which case the pressure also rises.
How to fix the situation with a drop?
Everything is extremely simple here. First, you need to take a look at the pressure gauge, which has several characteristic zones. If the arrow is in green, then everything is fine,and if it is noticed that the pressure in the heating system is dropping, then the indicator will be in the white zone. There is also a red one, it signals an increase. In most cases, you can manage on your own. First you need to find two valves. One of them is used for injection, the second - for bleeding the carrier from the system. Further, everything is simple and clear. If there is a lack of carrier in the system, it is necessary to open the discharge valve and follow the pressure gauge installed on the boiler. When the arrow reaches the required value, close the valve. If bleeding is needed, everything is done in the same way with the only difference being that you need to take a vessel with you, where the water from the system will be drained. When the gauge needle shows the norm, tighten the valve. Often this is how the pressure drop in the heating system is "treated". Now let's move on.
What should be the working pressure in the heating system?
But to answer this question in a nutshell is quite simple. A lot depends on which house you live in. For example, for autonomous heating of a private house or apartment, 0.7-1.5 atm is often considered normal. But again, these are approximate figures, since one boiler is designed to operate in a wider range, for example, 0.5-2.0 atm, and the other in a smaller one. This must be seen in the passport of your boiler. If there is none, stick to the golden mean - 1.5 atm. The situation is quite different in those houses that are connected to the centralheating. In this case, it is necessary to be guided by the number of storeys. In 9-story buildings, the ideal pressure is 5-7 atm, and in high-rise buildings - 7-10 atm. As for the pressure under which the carrier is supplied to buildings, most often it is 12 atm. You can reduce the pressure with the help of pressure regulators, and increase it by installing a circulation pump. The latter option is extremely relevant for the upper floors of high-rise buildings.
How does carrier temperature affect pressure?
After the closed water supply system is installed, a certain amount of coolant is pumped. As a rule, the pressure in the system should be minimal. This is because the water is still cold. When the carrier heats up, it will expand and, as a result, the pressure inside the system will increase slightly. In principle, it is quite reasonable to regulate the number of atmospheres by adjusting the temperature of the water. Currently, expansion tanks are used, they are also hydraulic accumulators, which accumulate energy inside themselves and do not allow an increase in pressure. The principle of operation of the system is extremely simple. When the operating pressure in the heating system reaches 2 atm, the expansion tank is switched on. The accumulator takes away excess coolant, thereby maintaining the pressure at the required level. But it happens that the expansion tank is full, there is nowhere for the excess water to go, in this case a critical overpressure (more than 3 Atm.) may occur in the system. To save the system from destruction, a safety switch is activated.valve that removes excess water.
Static and dynamic pressure
If you explain in simple terms the role of static pressure in a closed heating system, then you can put it something like this: this is the force with which the liquid presses on the radiator and pipeline, depending on the height. So, for every 10 meters there is +1 Atm. But this applies only to natural circulation. There is also dynamic pressure, which is characterized by pressure on the pipeline and radiators during movement. It is worth noting that when installing a closed heating system with a circulation pump, static and dynamic pressure are added, while taking into account the features of the equipment. So, a cast-iron battery is designed to work at 0.6 MPa.
Diameter of pipes, as well as their degree of wear
You need to remember that you need to consider the size of the pipe. Often, residents set the diameter they need, which is almost always slightly larger than standard sizes. This leads to the fact that the pressure in the system decreases somewhat, due to the large amount of coolant that will fit into the system. Do not forget that in the corner rooms the pressure in the pipes is always less, since this is the most remote point of the pipeline. The degree of wear of pipes and radiators also affects the pressure in the heating system of the house. As practice shows, the older the batteries, the worse. Of course, not everyone can change them every 5-10 years, and it is not advisable to do this, but from time to timePrevention doesn't hurt. If you are moving to a new place of residence and you know that the heating system is old there, then it is better to change it right away, so you will avoid many troubles.
About leak testing
It is mandatory to check the system for leaks. This is done to ensure that the heating operation is efficient and has no failures. In multi-storey buildings with central heating, the cold water test is most often used. In this case, if the water pressure in the heating system drops by more than 0.06 MPa in 30 minutes or 0.02 MPa is lost in 120 minutes, it is necessary to look for places of gusts. If the indicators do not go beyond the norm, then you can start the system and start the heating season. The hot water test is carried out immediately before the heating season. In this case, the media is supplied under pressure, which is the maximum pressure for the equipment.
Conclusion
As you can see, dealing with this issue is quite simple. If you use autonomous heating, then the operating pressure in the system should be approximately 0.7-1.5 atm. In other cases, much depends on the number of storeys of the building, as well as the degree of wear of batteries and radiators. In all cases, care must be taken to install an expansion tank, which will eliminate the occurrence of water hammer and, if necessary, reduce the pressure. Remember that it is desirable at least 1 time in 2-3 years beforeduring the heating season, clean pipes from scale and other decay products.
