Leaks inside the boiler
The second type of leaks are leaks inside the boiler. Inside the boilers there are units in which water can leak. Problems like this are usually easy to spot. Items that may leak include:
- Auto air valve;
- Explosive valve;
- Three way valve;
- Expansion tank.
The first node that can leak is the auto-air valve. It stands at the top of the pump and has a small cap from which drops of water can escape along with the air that is formed in the heating system. These drops can dry out, but this happens in rare cases, usually they start to come out of the boiler.
The problem with the auto air valve is very common. This happens if the auto-air valve is not inspected, cleaned and changed on time.
The second leak node is the explosion valve. Some people run the blast valves through the wall to the street with a pipe so as not to flood the kitchen or another room under the boiler, depending on where the boiler is located.
This is usually advised by the workers who installed the boiler. They recommend leading the tube into the sewer or through the wall to the street. It often happens that pressure escapes through this explosion valve. The explosion valve once worked, a grain of sand or something got in there, and now water is slowly oozing from it.
To check the explosive valve for leakage, you need to take a hand tube that departs from it. If the tube is warm or hot about a meter away, then the problem is most likely in the explosion valve. In this case, you should dismantle the tube and check visually whether water is dripping or not.
The third possible leakage hydraulic unit is a three-way valve. This valve switches between heating and hot water. It often happens that such nodes that are responsible for switching fail. This indicates that the servo is broken. In this case, water will flow out, and the pressure will drop.
The fourth leak point may be the expansion tank. There is no air in this tank. It has a membrane, thanks to which air is pumped in one direction, and pressure from the heating system goes to the other.
If the expansion tank is out of order, then there is no compensation in it - the water has pressed completely against the expansion tank. When the temperature on the boiler drops, the heating system cools down, and the pressure, which was, for example, 1.5 bar, drops to almost zero or to a value at which the boiler can no longer turn on. Usually this value is 0.5 bar.
These are all the main reasons why the pressure in the heating system may drop. Of course, there are other reasons that can lead to this problem.
In order to identify the cause of the pressure drop in the heating system as soon as possible, you should contact the specialists. Thanks to their qualifications, experience and knowledge in the field of design and proper installation of heating systems, they will be able to quickly find the cause and eliminate the malfunction.
The optimal value for a private house or cottage
Any boiler operates under certain system settings, in particular, it is necessary to correctly calculate the water pressure. This value is affected by the number of storeys of the building, the type of system, the number of radiators and the total length of the pipes. Usually, for a private house, the pressure level is 1.5-2 atm, but for a multi-apartment five-story building, this value is 2-4 atm, and for a ten-story house, 5-7 atm. For higher buildings, the pressure level is 7-10 atm, the maximum value is reached in heating mains, here it is 12 atm.
For radiators that operate at different heights and at a fairly decent distance from the boiler, constant pressure adjustment is required. At the same time, special regulators are used to reduce, and pumps are used to increase. But the regulator must always be in good condition, otherwise sharp fluctuations and drops in the temperature of the coolant will be observed in some areas. Correction of the system must be carried out so that the shut-off valves are never completely closed.
Air lock as a cause of pressure increase in closed systems
When a closed system is operating, it is not uncommon for the pressure to increase, while it may be accompanied by a decrease in the overall temperature of the coolant, blocking the boiler. All this leads to an imbalance in the operation of the circuit, the failure of its individual elements.
Why does the pressure in the system increase or is there a sharp increase? Usually in closed heating circuits using gas equipment or other types of boilers, such drops occur due to airing. Air pockets are a fairly common cause of pressure drop. Typically, the presence of such problems is determined in the following cases:
- equipment breakdown;
- incorrect start of the system;
- failures in the operation of automation;
- presence of cracks in the boiler heat exchanger.
There are several reasons for such failures in the system:
- the contour is filled from the top point;
- at start-up, a very rapid filling of water in the system is observed;
- Mayevsky taps or air vents are faulty;
- in heating radiators after their repair, air was not bled;
- the impeller of the circulation pump is loose, that is, air is pumped with violations.
Depressurizing the heating system, filling it with water from a low point with open taps to bleed air will help solve the problem. The filling itself should be slow, the work ends when water begins to flow from the top of the circuit. In addition, after installing the heating system and before starting its operation, it is recommended to treat the air vents with ordinary soap foam. This allows you to detect air suction and prevent the formation of air pockets in time.
Low water pressure in the boiler what to do
If no leaks are found in the radiators, then the reason why the pressure disappears lies in the boiler. Why does this happen and how to raise (gain, pump up, increase) pressure? If you often pump water, and the boiler does not hold pressure, there is a possibility that microcracks have formed in the heat exchanger. When the boiler is heated, the cracks increase and leakage occurs. The intervention of a specialist is urgently required, or you can eliminate the fistula with your own hands.
Heat exchanger soldering
The reason for the appearance of microcracks is the wear of the heat exchanger, frequent washing with reagents, the poor quality of the metal from which it is made, water hammer with a sharp increase in pressure in the line. They happen, as a rule, after accidents in water mains.
Places where there are microcracks can be identified by a layer of scale. If it is easy to remove the heat exchanger, you can try to solder them. Bithermic heat exchangers are almost impossible to repair due to design features, it will have to be changed.
The boiler does not rise (does not gain) pressure when the feed valve flows. If the pressure in the line is higher than the pressure in the boiler, the liquid through the make-up valve increases the pressure in the boiler to a critical point, and it is discharged through the safety valve.
As a result, the pressure decreases, the water from the heating system squeezes the liquid in the plumbing and heating system. Close the tap, check the tightness of its connection or change, in case of malfunction.
The pressure is turned off (drops) to 0 if the three-way valve fails.Large pieces of scale or rust may get into the valve and block the flow, clean the valve.
A problem with the expansion tank can cause pressure changes. When heated, the volume of water in the system increases, this excess enters the expansion tank. There is a rubber membrane inside the tank.
The space between the outer wall and the membrane of the tank is filled with gas. Excess liquid fills the membrane and the pressure in the heating system is released. The gas equalizes the excess pressure.
After the temperature drops, the liquid again enters the system. This does not happen when there is a gas leak. The cause of the compensation tank not working properly is a worn nipple that needs to be replaced. Worse, when the membrane is torn, you will have to change the tank itself.
Sectional expansion tank
To pump air into the compensation tank, you can use a car pump. How to add (submit, pump up) pressure in the expansion cistern?
basic information
A modern house is a complex system of communications, automation of units allows you to reduce interference in their work to a minimum. Despite this, owners of heating systems face a number of problems. Experts identify five main reasons for the pressure drop in a closed heating system:
failure of the radiator;
installation errors;
discrepancy between the power of the boiler and the "native" pipeline;
depressurization and the appearance of a leak;
interruptions / jumps in the supply of gas.
Exercising control
According to modern standards, models of heating devices are equipped with control sensors. Their task is to monitor the pressure level and, during jumps, temporarily or completely block the operation of the unit and system. By displaying the error code on the information display of the boiler, the user can read the information in the instructions or find the answer on the official website of the manufacturer.
The most famous models of gas boilers support operation within 1.5–2 atm. Units of the Bosch, Ariston, Baxi brands, the Navien boiler - they are all produced with a forced fluid movement system and a pump, the pressure drop is controlled by the program.
Principle of operation
How does pressure work in gas boilers? Let us consider in detail the process of functioning of the equipment.
Turning on the unit starts the operation of the sensors, and from the first seconds the temperature of the coolant begins to be fixed.
The outdoor thermostat, if provided with the model, is automatically activated, and you see how the arrow lights up and heating is performed.
As the temperature rises, the pressure indicators rise, the water heats up and expands. The safety valve is periodically turned on, which dumps excess into the sewer.
The operation may fail if too much water goes into the drain - this leads to a drop in pressure.
The boiler switches off automatically when the temperature set by the program is reached.
What happens inside the expansion tank? It consists of two parts separated by a diaphragm. Excess fluid accumulates in one part, and nitrogen accumulates in the second. The coolant fills the tank as much as the difference between the nitrogen values \u200b\u200band the system value is. Having reached the temperature set by the program, nitrogen pushes water out of the tank by deforming the membrane - heating stops.
The main reasons for the increase in pressure
Most often, the reason why the pressure in the heating circuit in a closed heating system rises is equipment failure, due to which the indicators either jump up or drop sharply down. But other than that, the reasons also include the following:
- A sharp increase in coolant pressure due to closed shutoff valves. An increase in pressure is observed in the system, after which the boiler is blocked and the system stops.To eliminate the problem, it is necessary to check the fittings for leaks, open valves and taps to relieve pressure.
- The reason for the rise in pressure in the heating system may be contamination of the mud filter. Rust particles, debris, sand and slag accumulate on the surface of such a filter. As a result, pressure rises strongly in the area between the boiler and the filter. To eliminate the cause, it is necessary to clean the filters regularly, at least 3-4 times a year. It is also a good solution to replace conventional mud collectors with magnetic or flush filters. They cost more, but their maintenance is much easier.
- The working pressure of the system may increase due to a malfunction of the boiler automation. This is a factory defect, incorrectly performed system settings, a breakdown of the control board. All these problems require repair of the boiler, which can only be carried out by a master.
- There are leaks in the make-up tap, that is, water will constantly penetrate into the common circuit, which causes a pressure surge. Repair is usually quite simple, you just need to replace the rubber gaskets. But if there is a marriage, the crane or equipment should be completely replaced.
Why does pressure drop in a double-circuit or conventional boiler? This situation most often occurs when the expansion tank breaks down or the air valve passes. To fix the problem, it may be necessary to repair or completely replace the tank.
