Grows pressure in the boiler. Copper gas wall double-circuit. Repair Part 2
Hello, dear visitors! We continue to consider such a problem when the pressure in the dual-circuit boiler does not correspond to the norm.
In the last note on the same topic, the reasons for which in the two-circuit boiler is not stable, it falls, it grows. Or for example, it changes after turning on / off the DHW and so on, in general, if the pressure you have some way jumps, then feel free to go to this article, it is just for these cases.
And in this article, it came to core to find out the reasons why the pressure in the boiler is constantly growing. Only up! And it will grow until the safety valve of pressure emergency discharge will work.
Considering that the principle of operation of most boilers is similar, then this malfunction can manifest itself in various models. But, I will tell on the example of the ARISTON CLAS 24 FF boiler since the boiler is this model used by me.
Optimal pressure in the gas boiler
On average, the pressure rate is 1 or 2 atmosphere. In high-rise residential buildings, permissible to 2-3 atmospheres. The limit value in the systems of the closed view is 2.4 bars. Modern models have a pressure gauge with an arrow that indicates the level of pressure. However, if the boiler does not have a built-in pressure gauge, then they need to get.
Pressure measurement is often not enough to carry out full diagnostics. You need to install these devices on the pipe, near the pump and in the system itself. Measurement check does not directly affect the operation of the equipment, but it helps to detect the defects and solve it. Manometers themselves should also be checked for good.
Consequences of instability in contours
Insufficient or higher pressure in the thermal circuit is equally bad. In the first case, some of the radiators will not effectively heat the premises, in the second. the integrity of the heating system will be disturbed, its individual elements will fail.
Proper strapping will allow you to connect the boiler to the heating circuit as it is necessary for high-quality work of the heat system
The growth of dynamic pressure in the heating pipeline occurs if:
- The coolant is too superheated;
- The pipe cross section is insufficient;
- boiler and pipeline covered with science;
- air traffic jams in the system;
- A too powerful increase in the rising pump is installed;
- Water feeding occurs.
Also increased pressure in the closed circuit causes incorrect balancing with cranes (the system is regulated) or a malfunction of individual valve regulators.
To control the operating parameters in closed heating circuits and security group is installed for their automatic adjustment:
For the formation of a security group required for normal operation in the heating system
As part of a group used for automatic adjustment and pressure control in the system, there is a pressure gauge, piston air vent and safety valve
The security group is installed behind the boiler on the pipe supply pipe of the DVLC pipe systems and on the feed part of the main pipe system
The functional components of the Security Group provide an output into the atmosphere of air that threatens the formation of traffic jams and excess pressure, and the coolant increasing in the volume when boiling
The security group must include in systems with closed expansion tanks that have no natural ability to reduce pressure as open contours
In the collector versions of heating requiring the use of circulation pumps, the security group is complemented by duplicate air vents on camshafts
Refuse to install the security group is permissible if the heating of the coolant is carried out by a boiler equipped with its own set of similar means in miniature. Example: Gas wall boilers, part of floor and pellet
Security group components can be located in different places of the system, but it is important to observe one condition. Safety valve must be above the boiler
The pressure in the heating pipeline falls for the following reasons:
- leakage of the coolant;
- pump malfunction;
- breakthrough of the membranes of explicit, cracks in the walls of a conventional expansion tank;
- security unit malfunctions;
- Water leakage from the heating system in the feeding contour.
Dynamic pressure will be elevated if the cavities of the pipes and radiators are clogged if the trap filters are contaminated. In such situations, the pump operates with an increased load, and the effectiveness of the heating circuit decreases. The standard outcome of the exceedment of pressure values become leaks in connections and even breaking pipes.
Pressure parameters will be lower than it is necessary for a normal functionality if the insidual power pump is mounted in the highway. It will not be able to move the coolant with the required speed, it means that a somewhat cooled working environment will be supplied to the device.
The second bright example of the pressure drop. the duct is blocked by a crane. The sign of these problems is the loss of pressure in a separate segment of the pipeline, located after the obstacle to the coolant.
Is Your Central Heating System Losing Pressure?
Since all thermal circuits have devices protecting from excessive pressure (at least safety valve), low pressure problem occurs significantly more often. Consider the reasons for the fall and ways to increase the pressure, which means to improve the circulation of water, in the heating systems of open and closed type.
Ways to raise pressure in the boiler
This problem is solved by different ways, depending on which cause is caused by its fall.
In the case of leaks identified by visual or thermal imager, the problem is eliminated by a suspender or compound sealing or a complete replacement of the node.
note! Before pumping pressure at breaks in the expansion tank of the boiler or injury nipple, this item must be replaced with a new. In difficult situations, it is necessary to replace the tank itself.
Cracks of heat exchange elements of the boiler are visualized by long observation or using specialists, after which it is necessary to sew damaged contour portion.
To eliminate air s in the system, you must turn off the column, open the valve on the crane of Maevsky and pull out all air, after which the heat carrier should add to the normalization of pressure in the system. All bugged noises should disappear.
With the unclosed crane on the discharge of the coolant, it must be trusted to complete closure, pre-checking the density of the clamp.
The difficult situation happens when the pressure in the thermal circuit is dropped inside the walls, the pipes are firmly mixed into the framework of the building. Therefore, for such designs it is better to choose durable and reliable materials.
Additional Information. When performing repair work, it is necessary to objectively assess its technical knowledge and in difficult situations to contact the specialists.
Examples of pressure drop in heating system
Example of the first
Suppose you come in the interval between the work of the pump, saw that the pressure fell. Reinforced it to the standard position. And gone. Next, the boiler performed a cycle of one-time workout, heated and cooled, and you may not know that at this time there was a safety valve. And not knowing this, you again have to feed the pressure, not understanding the true reason for what happened with the coolant and why the pressure drops so fast.
Example of the second
For the second example, we will give an even more concrete case. There is an indirect heating boiler, the German company Vaillant, installed in it, the serpentine on some unbearable plot was told. And there was an association of the area of sanitary water and water with water from the coolant. This leads to the fact that when the wicked pressure in the water supply system is high, then the plumbing water enters the heat carrier region and increases the pressure in the system. And with a decrease in the pressure of sanitary water, along with it and drops pressure in the heating system.
Unfortunately, the only way out of this situation is a complete replacement of an indirect heating boiler.
For the third example, we will look at dual-circuit heating boilers. One of the most frequent reasons why pressure drops in the heating system is initially incorrecting the size of the boiler. This is one of the cases when instead of small heating radiators, characterized by the size of the saved coolant, are installed pipes that use a much larger amount of water. And this fact is not taken into account in the initial adoption of the necessary area of premises in which heating will be carried out.
Consequently, in the calculations made by you, exactly the same error and will lead to a drop in pressure in the heating system.
What pressure is normal and how to control it
The heating system negatively affects both excessive high and low pressure, which is measured in the atmosphere. There are several more types of pressure:
- static. denotes the pressure of gravity to the coolant (increases by 0.1 bar with each increase of 1 meter);
- Dynamic. Created by a pump, or with an increase in temperature, which leads to the expansion of the coolant;
- Working. the amount of static and dynamic pressures. In private houses, the level of 1.5-2 atmosphers (or bar) is considered normal. In high-rise buildings, this value can be slightly higher than the norm, because the pipes must withstand the hydrowards (temporary excess of the pressure rate).
- Maximum. upper limit for the operation of the heating system. In this case, even short-term pressure exceeding can lead to an accident (breaking of pipes, radiators or a heat exchanger of the boiler).
Water operating pressure is measured by pressure gauge. Almost all manufacturers are embedded in their modern models of gas boilers analog or electrical varieties of this device. To improve security, experts recommend installing an additional pressure gauge, for example, on the boiler. In this case, even if the main device fails, you will always be able to monitor or compare readings.
In addition to the pressure gauge, in the gas boiler must be necessarily provided:
How does the work of the hydroaccumulator affect the pressure
Problems with expansion tanks that affect the pressure in the heating circuit, very common. Incorrectly calculated expansion volume. one of the most characteristic prerequisites.
Violations in the paper may result in incorrect installation, low or high pressure in the air chamber of the tank, damaged membrane. each cause can lead to a violation of the circulation of the coolant in the system.
Expansion tank: device features and volume
If a small volume is installed in the heating system, it cannot compensate for the expansion of heating water when heated. At a temperature of 85-95 ° C, water is expanding about 4% and its extra volume exits through a safety-reset valve.
So that the expansion is fully fulfilled its compensatory function, its capacity for systems with a gas boiler should be at least 10 percent of the total water in the circuit.
If you install a tank with a volume of more norm, then pressure fluctuations will be even less. Reducing drops in pressure positively affects the operation of the system and the life of heating equipment
Damage to the tank membrane leads to the fact that the water completely fills its volume and the pressure in the circuit falls. If you fill out the outline of the contour by opening the fuel tap, it will create a new problem. when heating the heat carrier, it will not be expanding and the pressure in the system will increase more than the norm. Correct the situation only by replacing the rubber partition.
Installing the tank follows only on the pitch pipe, in front of the heating boiler. So the tank will minimally affect the operation of the circulating pump, which is installed after the gas boiler. In addition, there is a water temperature below and a negative impact on the pressure in the system and the tank membrane will be less.
Pressure setting in the air chamber
The pressure generated in an air chamber may also lead to an increase or drop in the pressure inside the heating system. Check and pump air in the tank only in the absence of heat carrier in the tank.
To do this, it is necessary to overlap with the help of shut-off valves access to the overall contour and pull the water through the drainage drain. Then the pressure in the air chamber is measured and pumped / descend to the necessary values.
Check the pressure indicators in the expansion tank can be using a car pressure gauge, pump it. with the help of a car pump
To adjust the pressure of the expansion tank in the air chamber should be 0.5 bar higher than the estimated limit pressure in the system. After the pressure in the leveling part of the tank is adjusted, the contour of cold water is carried out to the intended pressure value.
Then the air from the air chamber is descended until the pressure in the heating circuit and the tank will begin simultaneously drop. it is necessary to simultaneously follow the pressure in the system and in the expansion tank.
In this phase, the changes in indicators are little noticeable, so it is necessary to be ready for the immediate cessation of air leveling from the expansion tank, as soon as the simultaneous decrease will be found.
How to solve the pressure problem?
The very first thing to be taken in such cases is to check the valve. Before checking, make sure that the feed crane is most closely closed. Check what happens when the gas boiler is in the off state. To do this, disconnect it from the power supply. The same thing happens even in the off state. the solution is one thing. call the service service, which will replace your crane. Replacing the crane yourself at home is not recommended, as special equipment may be required to perform this work.
If the pressure will be reduced only while the boiler is turned on, and this does not occur during the use of warm water, but only when the boiler is turned off, then the reason for the breakage is most likely in the expansion tank. Eliminate the fault will easily work out and at home. Quite an external inspection to find a malfunction, most often it is some kind of scratch or a small hole, then patch it with special glue. If the platform is large, then the help of specialists will need or complete expansion tank replacement.