Reasons for increased pressure. Ways to solve the problem
You can tell if there is too much pressure in the system by looking at the pressure gauges. Normal readings are 1-2.5 Bar. If the pressure gauge needle reaches 3 Bar, sound the alarm. If the increase is constant, it is urgent to find the cause and reduce the pressure.
Also pay attention to the safety valve: it will constantly release water to relieve pressure
The problem is in the expansion tank
This tank can be located separately from the boiler or be part of the structure. Its function is to collect excess water when heating. Hot liquid expands, it becomes 4% larger. This excess is sent to the expansion tank.
The size of the tank is affected by the power of the boiler. For gas equipment, its volume is 10% of the total amount of coolant. For solid fuel - 20%.
Membrane rupture. If a part is damaged, the coolant is not restrained by anything, so it completely fills the compensation tank. Then the pressure begins to drop. If you decide to open the tap to add water to the system, the pressure will rise above normal. The connections will leak.
The tank or membrane needs to be replaced to reduce the pressure.
The pressure is below or above normal. A machine pump will help to achieve normal values (nominal) in a gas boiler.
- Drain all water from the system.
- Close the valves.
- Pump the circuit until you are sure there is no water.
- How to bleed air? Through the nipple on the other side of the inlet.
- Download again until the indicators reach the norm specified in the instructions for Ariston, Beretta, Navien and other brands.
The location of the tank after the pump provokes water hammer. It's about how the pump works. When it starts, the pressure rises sharply and then drops as well. To avoid such problems, in a closed heating system, install the tank on the return pipe. The next one to cut in is the pump in front of the boiler.
Why does pressure increase in closed systems?
Air accumulates in a double-circuit boiler. Why does this happen:
- Incorrect water filling. The fence is carried out from above, too quickly.
- After the repair work, excess air was not released.
- Mayevsky's air release valves are broken.
The pump impeller is worn out. Adjust or replace the part.
To relieve or reduce pressure, fill the fluid correctly. The intake is carried out from below, slowly, while the Mayevsky valves are open to bleed off excess air.
Open system problems
The problems are the same as described above
It is important to fill water and bleed air correctly. If after this the pressure does not return to normal, it is necessary to drain the system
Secondary heat exchanger
The unit is used to heat hot water. Its design consists of two insulated tubes. Cold water flows through one, and already heated water flows through the other. If the walls are damaged or a fistula appears, the liquids mix and enter the heating part. Then the pressure increases.
If you do not want to repair and solder the heat exchanger, you can replace it. To do this, buy a repair kit and get to work:
- Close the supply valves.
- Drain the water.
- Open the case and find the radiator.
The unit is secured with two bolts. Unscrew them.
- Remove the faulty part.
- Install new gaskets at the fastening points and connect the heat exchanger.
Other reasons
There are other reasons for such problems:
- The fittings are blocked. When collecting, the pressure increases and protective sensors block the equipment. Inspect the taps and valves, unscrew them until they stop. Make sure the valves are working properly.
- The mesh filter is clogged. It becomes clogged with debris, rust, and dirt. Remove and clean the part. If you do not want to clean regularly, install a magnetic or flush filter.
- The feed tap has failed. Perhaps its gaskets are worn out, then you can get by with a replacement. Otherwise, you will have to change the tap.
- Problems with automation. Faulty thermostat or controller. The reason is wear and tear, manufacturing defects, or incorrect connection. Diagnostics and repairs are carried out.
Check whether the boiler protection parts are in good working order: pressure gauge, valve, air vent. Clean radiators and other components from dust, soot, and scale. Prevention helps prevent serious breakdowns of gas equipment.
What is the nominal pressure in a gas boiler, how to check it
What pressure should be in a gas boiler is the indicator declared by the manufacturer at which the equipment works properly.
It is important to know and monitor changes in values during equipment operation. Strong surges can lead to equipment failure and emergency situations. Let's figure out how to properly monitor and maintain the operation of the boiler.
Normal pressure readings
There are no pressure standards for autonomous heating systems. This value is calculated depending on the equipment parameters and pipe characteristics. In this case, it is necessary to follow the rule that the normal pressure in the heating must correspond to the minimum value of the “weakest” element.
The next factor is the required difference between the pressure in the forward and return pipes of the boiler. It should be 0.3-0.5 atm. This is one of the mechanisms for maintaining normal coolant circulation.
Average values are in the range from 1.5 to 2.5 Atm. , depending on the parameters of the entire heating system. The pressure calculation is carried out at the design stage and takes into account all factors - characteristics of equipment, components, number of floors of the house.
What should be the normal pressure in a gas boiler?
The value may vary for each brand and model of equipment. Exact indicators can be found in the passport data. The average gas pressure depends on the boiler design:
The “minimum” column indicates the value below which the boiler will not operate. Safety automation will turn it off to avoid serious damage or accident.
In a European-type gas supply system, the nominal value is 20 mBar, while in our regions it is 12–18 mBar. Consumption depends on the type of fuel consumed: liquefied or main fuel.
In addition, there are other types of pressure - water and atmospheric. Water is designated by the unit of measurement Pa. Until the system is filled with water, the atmospheric pressure is maintained at 1 bar.
Values in expansion tank and heating system
The expansion tank is used to collect excess fluid. During heating, the liquid expands, which leads to an increase in values (norm 1.5 Bar). To avoid breakdowns, excess is taken into the reservoir and, after cooling, returned to the system.
A pressure gauge is installed to measure pressure. When changes occur, the pressure gauge needle points to the minimum or maximum permissible value. To change the situation, air is injected using a nipple.
To install the tank correctly, do this:
- Find out the rating for your model. The setting in the expansion tank should be 0.3 atm lower than in the heating circuit.
- Set these values before connecting the tank.
- After connecting, fill the circuit with liquid. Watch the pressure gauge for changes. As soon as they reach the norm, turn off the water supply.
- Start the pump.
- Set the thermostat to the highest temperature. This is done so that the liquid expands as much as possible and fills the expansion tank.
The higher the speed of the circulation pump, the faster the coolant moves through the system
Therefore, the pressure force is greater. There are no specific indicators of the nominal pressure in the circuit. It is believed that the difference in pressure force in the inlet and return pipes should not exceed 0.3–0.5 Atm.
What is the working pressure in the heating system
Pressure in the heating system occurs as a result of several factors. It characterizes the effect of the coolant on the internal walls of the elements (boiler, pipes, radiators). Until the water is filled, the pressure in the pipes will be equal to atmospheric pressure - 1 bar. But as soon as the process of filling water begins, this indicator begins to change.
Even with cold coolant, water pressure will be exerted on the pipeline. This is due to the different arrangement of the system elements - with an increase in height of 1 meter, 0.1 bar is added. This type of impact is called static. It is typical for open heating systems with natural circulation. Their design makes it possible to almost instantly stabilize possible deviations in the indicator.
In a closed heating system the situation is somewhat different. Since the coolant expands during heating, excess pressure forms in the pipes. Depending on the design of the highway, it may vary in different sections. If during design you do not provide for the installation of stabilizing devices and indicating devices, then a breakdown may occur as a result. Along with this, there are other reasons for the drop.
Exceeding the normal value may be due to the following factors:
- Natural expansion of the coolant volume due to heating.
- Incorrect pipe diameters. The boiler outlet pipe must be the largest size. If this rule is not observed, then as the diameter decreases, the pressure increases.
- Increased power of the circulation pump or malfunctions in its operation. The result of the latter may be water hammer.
- An open tap for recharging the system from the water supply. This happens if the pressure in the water supply pipes exceeds that in the heating system.
The reason for the drop in the nominal pressure indicator can only be a leak. In some cases, this is a microcrack in the pipe or, most often, in the boiler heat exchanger.
Pressure drop
An increase in pressure in closed heating systems is not the only problem; in some cases there is a sharp drop in operating pressure, and among the reasons why the pressure level drops, the following should be highlighted:
- hidden system leaks, corrosion, loose connections, leaking fittings;
- rupture of the tank membrane, which requires replacement or repair of equipment;
- pressure drops in the system are observed, if the nipple poisons, such an air leak leads to deflation of the tank, and this causes damage to the membrane;
- there are cracks on the boiler heat exchanger, which leads to coolant leakage;
- pressure drops associated with the appearance of air bubbles lead to a decrease in the overall temperature in the system and its shutdown;
- One of the reasons for the decrease in pressure may be a soured or slightly open tap used to discharge water into the sewer system.
Heating system pressure
Very often, boiler buyers have no idea about the pressure in the heating system. But the consequences of excessively high blood pressure are very dire. In the best case, the heating boiler will simply swell, a weld may burst or a leak will occur in the heating system. In the worst case, the boiler can simply explode and cause great damage to property and health.
When designing a heating system, special attention must be paid to the selection of protective and safety devices. Each boiler manufacturer specifies the operating pressure and the maximum permissible pressure in the heating system. Therefore, before starting installation of the heating system, make sure that all components are selected correctly and the maximum permissible pressure in the heating system will not be exceeded.
Most of our boiler buyers prefer to use membrane expansion tanks in heating systems. Therefore, we provide a formula for calculating the recommended volume of a membrane expansion tank:
where Vco is the total volume of coolant in the heating system (can be accurately determined when filling the heating system or by calculation),
K is the coefficient of expansion of the coolant from a cold state to the maximum temperature (up to 95 degrees). For water we take this coefficient to be 5%. When using non-freezing liquids, the expansion coefficient increases and depends on the percentage of components. When using antifreeze liquids based on various glycols, it may be necessary to use this coefficient equal to 7-8%, provided that the concentration of propylene glycol or ethylene glycol is high.
Pmax is the maximum permissible pressure in the heating system. For START boilers, the pressure is 1.5 atm.
Po is the initial pressure in the “cold” heating system. As a rule, this pressure is determined by the maximum height of the water column of the heating system. If the height of the water column is 10 m, the pressure will be 1 atm.
Please note that membrane expansion tanks are initially inflated with excess pressure. Therefore, when connecting the tank to the heating system, it is necessary to equalize the pressure in the tank to the pressure in the heating system in its cold state. For this purpose there is a nipple like on car tires. Violation of the procedure for equalizing the initial pressure in the tank can lead to ineffective use of the expansion tank and excess pressure in the heating system when the boiler is operating.
In addition, in a closed heating system it is necessary to provide safety valves with an operating pressure of 1.5 atm. We recommend installing at least 2 valves, as there are times when the valve does not work or does not have time to relieve pressure.
This formula is used for absolutely any boilers - gas, solid fuel, pellet and liquid fuel.
How to increase the pressure in the boiler
If the pressure drops due to the expansion tank, it means that its volume is incorrectly calculated or the internal membrane is damaged. The situation can be corrected by more accurately calculating the required volume or by replacing the tank.
If the pressure in the heating system drops immediately after it is first started, then this is normal. The newly filled circuit, if it was filled with ordinary tap water, is full of air. As soon as it is converted into bubbles and removed from the pipes, the circuit parameters are normalized. You can also try removing the bubbles manually by using a manual air release.
The worst thing is if the pressure in the system laid inside the walls and floors has dropped - the pipes are often masked and completely recessed in building structures. If something happens to them, you will have to suffer thoroughly to localize the problem. The situation can be prevented by more careful selection of materials for the construction of the heating circuit.
Before increasing the pressure, it is necessary to check the tightness of the system. To do this you need to inspect:
- All heating devices - often leaks form where they connect to the pipes. Leaks between individual sections are also possible;
- Pipes - microcracks often lead to leakage of coolant, due to which the pressure gradually drops;
- Fittings are another common place for coolant leaks to occur;
- Boilers - double-circuit models have a complex internal structure; it is necessary to inspect the circulation pump, three-way valve and heat exchanger.
It is best if a specialist inspects the double-circuit boiler.
Increased pressure in the heating system causes unbalanced operation of the equipment and frequent boiler blockages. As a result, individual elements are subjected to increased load, which leads to circuit breakdowns and equipment failure. Why does the pressure in the heating system increase? There are several reasons for this phenomenon, most often these are leaks, unbalanced operation of individual elements, failure of automation or incorrect settings.
What pressure should be in the heating boiler?
The operation and efficiency of the heating boiler directly depends on whether the pressure in your heating system is correct. And hence - the microclimate in heated rooms, safety, reliability and durability of the equipment. We propose to consider what pressure should be in the heating boiler, how to control it and why it can fall or increase.
Basic Concepts
First, let's look at the features of pressure and key concepts.
- There are several units for measuring pressure: atmospheres, bars, megapascals.
- Even in a non-working unit there is pressure - it is called static.
- During boiler operation, all network elements are subject to dynamic pressure.
- The maximum permissible pressure is the extreme value after which an accident can occur.
- The internal boiler radiator is the most sensitive part of the system, especially susceptible to pressure surges. But batteries and pipes can easily withstand quite high values, although much depends on the material from which they are made, their “age” and other parameters.
What pressure should be in a gas boiler strongly depends on the characteristics of the system itself - the number of batteries, equipment used, materials, etc. If you have a one- or two-story private house, the operating pressure should not exceed 1.5-2 atmospheres. If the number of floors is more than two, a higher value is allowed - up to 4 atmospheres. But in both cases, we recommend installing pressure gauges on each floor. This will allow you to take accurate readings and take action if necessary.
Features of closed and open systems
There are two popular types of heating systems in use today:
- Open.
The water here moves naturally due to its special design and the force of gravity. The system itself communicates with the atmosphere through an expansion tank. - Closed.
Here the circulation of the coolant is carried out under the action of a circulation pump.
It is closed systems that are most popular today. For them, the normal operating pressure is no more than 2 atmospheres. But if the circuit is long, then the pressure may be higher. In some cases, several pumps are even installed to ensure normal coolant movement along the circuit. It is recommended to install pumps in parallel - this minimizes the load on the boiler, allowing it to operate longer without damage.
Knowing what pressure in a gas boiler is normal, it must be constantly monitored. Modern units must have a pressure gauge installed, allowing you to immediately find out the real value. The advantage of built-in pressure gauges is that they do not require power to operate. Electronic ones do not work without electricity.
But one pressure gauge is not enough. To obtain objective values, you need to install additional ones at the inlet/outlet of the boiler, the upper/lower segments of the system, before and after the pump. Experts also advise installing pressure gauges at pipe branching points. The rule “the more the better” works here (within reasonable limits, of course). Several pressure gauges will allow you to better assess the situation throughout the entire circuit.
Unexpected rise and fall in pressure: causes and solutions
It is easy to find out what pressure should be in a double-circuit boiler - this information is publicly available. But finding the reason for incorrect values is more difficult. Let's look at a few common reasons.
Increase in pressure in the system
There are many reasons for a sharp drop in blood pressure:
- due to the increase in coolant temperature, its volume increased;
- the coolant stopped moving along the circuit due to a system malfunction or for another reason;
- the system is clogged or an air lock has formed in it;
- you or someone else accidentally closed the valve;
- there were errors during installation;
- The boiler power is set too high or there is a pump malfunction.
Modern boilers are equipped with expansion tanks that neutralize the expansion of the coolant when heated. There are also safety valves that protect the circuit from damage due to high pressure or even water hammer. If you see that the pressure values are close to critical, try reducing the boiler power. If the situation does not return to normal, contact a specialist. He will find the problem and fix it.
System pressure drop
There are two common reasons:
- the heat exchanger is faulty;
- there are leaks in the circuit.
This often occurs when individual elements of the system wear out. Microcracks appear, pipes rupture, and rubber membranes in the expansion tank are damaged. You can try to find the leak yourself. The most “problematic” places are pipe solders, connection points with batteries, etc. If you find a leak, then this is the reason for the pressure drop. It is much more difficult to find leaks if the pipeline is hidden in floors or walls. Here you cannot do without the help of a specialist, since out of ignorance you can, in search of a leak, dismantle the coating where this is not necessary. You will have to spend extra money on repairs.
For boiler repair and maintenance, contact Profteplo
Our company offers repair and maintenance services for heating boilers of all types from different manufacturers and different years of manufacture. If you see that the system is not working properly, contact us. Our manager can tell you what pressure should be in the electric boiler under your conditions of use, and whether there is any reason to worry.
Norm and control
We have already said that in a gas boiler the pressure should be within 1.5-2 atmospheres - this is the norm for a system that is put into operation and is in a heated state. In multi-storey buildings heated by centralized boiler houses, this figure is higher. Here, pipes and batteries must withstand not only high pressure, but also water hammer - this is an abrupt increase in pressure.
If drops are typical for centralized systems, then for autonomous heating they are rare - the volume of coolant here is not so large that serious jumps can be observed. In a cold state, the normal indicator is 1-1.2 atm., and in a warm state - slightly higher.
In private households, autonomous heating systems are used, powered by single-circuit and double-circuit boilers. The latter are becoming increasingly widespread. In addition to heating, they solve the problem of preparing hot water. One circuit in them heats the coolant circulating through the pipes, and the other ensures the operation of the hot water supply system.
Causes of pressure drop
If you find that there is low pressure in your gas boiler, there may be two reasons:
- The heat exchanger has failed.
- There are leaks in the heating circuit.
Any problems with the heating boiler must be identified and corrected as quickly as possible. A drop in pressure can be caused by a manufacturing defect, defects in the expansion tank, clogged heat exchanger, cracks or excessive wear. In any case, all problems should be corrected.
No less often, the pressure in the system drops due to leaks. In particular, they can occur in places of poor-quality soldering of plastic or steel pipes, at joints with radiators, in sections with great wear of the pipe, as well as in the presence of cracks in the rubber gasket in the expansion tank, which leads to coolant entering the air chamber.
You can establish a leak in the rubber membrane by pressing on the spool through which air enters the chamber. If water drips from it, the cause of the pressure drop has been found.
It is somewhat more difficult to detect leaks in pipelines if they run through a wall or under the floor. First of all, they diagnose visible sections of the contour and inspect the condition of the floor to detect stains from dried water. Salt deposits and signs of rust at the joints may also indicate depressurization of the system.
Some systems have the ability to turn off individual sections of the circuit one by one to make it easier to identify leaks.
If visual diagnostics of the condition of a closed pipeline does not produce results, perform pressure testing. This is done by professionals with experience and equipment. First, the coolant must be drained from the circuit, after which the batteries and the boiler are isolated.
Then air is pumped into the circuit, bringing the pressure in the system to a value 20% higher than the working one. After a few hours, the pressure level is rechecked. If it falls, they begin to search for a leak.
At the same time, on visible sections of the pipeline, the joints are lubricated with a soap solution. Where the soap begins to bubble and hiss, the seal of the circuit is broken.
Next, the defective seam is either sealed or the pipe section is replaced.
How to check the pressure in the heating expansion tank
Checking the pressure in the heating expansion tank is done with a hand-held pressure gauge, since in most cases the air chamber of the tank is equipped with a regular nipple, the same as on a car or bicycle wheel.
If we are talking about a wall-mounted gas boiler, the compensator is usually located on the back wall and is not so easy to get to, especially if the boiler is hanging in a niche or in a closet.
Therefore, it is most convenient to use a compact tire pressure gauge with the ability to record readings. If the test reveals that the pressure is insufficient, this must be corrected. Lack of proper pressure can cause trouble for the user in the form of emergency shutdowns of the boiler or release of excess pressure through safety devices.
It is not advisable to lead to such situations and according to the recommendations of most boiler equipment manufacturers - the pressure of the expansion tank should be monitored once a year during maintenance.
It is necessary to pump up the tank only when it is completely empty
Since it is structurally located on the boiler, it will be enough to drain the water from the boiler. You can pump up in any available way. Practice shows that the easiest way to do this is with a regular bicycle pump and check it with a hand pressure gauge. If the pressure in the air chamber of the expansion tank cannot compensate for the pressure in the water chamber, there is also a possibility of damage to the membrane or valve.
If there is no expansion tank
The expansion tank for a home heating network is the second most important element (after the boiler). Water, when temperature changes, changes in volume. The volume inside the circuit is always constant, so an expansion tank is additionally connected to the circuit, where excess coolant can be diverted, i.e. acts as a compensator. Consequently, the RB is a safety device that prevents emergency situations - increased pressure, depressurization of pipes, etc.
The use of boiler equipment without an expansion tank is highly not recommended.
For stable operation, the pressure of the RB must correspond to the system volume, because when replacing radiators with pipes, the volume of coolant must be increased. At the same time, a too large RB will not maintain the operating pressure in the circuit.
The standard is an expansion tank designed for 120 liters of coolant in the circuit (typical two-room apartment). If the tank is too small, then the water will be discharged when heating and expanding the volume through a safety valve. When the boiler is turned off, when the liquid temperature decreases, starting the boiler will be impossible, because its volume, and, consequently, the pressure will be insufficient. In such cases, additional network feeding is necessary.
https://youtube.com/watch?v=tgwLKEVRgYk%3F
Reasons for increasing pressure in the system
Sometimes, when checking the pressure in a closed heating system, the home owner may notice an increase in the indicators.
The reasons for the increase in pressure are:
- the coolant temperature in the circuit is too high, which has led to its excessive expansion;
- For some reason the water stopped moving along the contour;
- a valve is closed on one of the pipeline sections;
- an air lock or mechanical blockage has formed;
- the tap is not closed tightly, as a result of which water is constantly added to the boiler;
- the cross-section of the pipe entering and exiting the boiler does not meet the requirements;
- the pump power is higher than necessary, or it is not working correctly; problems with the pump can lead to water hammer inside the circuit.
Thus, it is important to find out what exactly caused the increase in pressure and solve the problem. Sometimes, in an efficiently operating system, a sharp surge in pressure occurs with the pressure gauge needle moving into the emergency zone. The reason for this is most likely that the water in the boiler has boiled. In this case, the fuel supply should be minimized as quickly as possible.
Most modern boilers for heating private houses have an expansion tank. This is a special sealed block, divided inside in two by a rubber partition. One compartment contains air, and the second contains hot water. If the water temperature is too high, the pressure increases and moves the baffle in the expansion tank to increase the size of the water reservoir and compensate for the difference.
In addition, boilers are equipped with safety relief valves, which are activated when the coolant boils or a critical pressure surge. They can be located either in the expansion tank or on the pipe leaving the boiler. When the maximum pressure in the heating system is reached, excess coolant is poured out through the valve, preventing damage to the circuit.
With proper design, bypass valves can be provided in the heating system. They allow you to redirect the coolant to a small circuit when a gap or air lock forms in the main circuit. This measure allows you to avoid overheating and breakdown of the heating system.
The performance of the components of the heating system must be periodically checked, since coolant leaks and violation of normal pressure levels in the expansion tank can lead to significant fluctuations in pressure in the circuit.
Best answers
amateur:
You must have a vent, an air vent. Put a hose on it so as not to get it wet, and quietly open the tap and try to relieve the pressure. (this is my opinion, but it’s better to call a specialist.)
Boss Heat:
Anywhere in the heating system where there is a drain valve (Mayevsky tap, radiator drain, etc.), open and drain into a jar or bucket. It is most convenient to turn on the relief valve on a wall-mounted boiler.
Eliseikin:
Look for a drain valve... there must be one!
alexm66:
The boiler has a drain valve (usually from the bottom). It usually opens with a key - there is no flywheel on it. The instructions for the boiler indicate its location. In this case, it is advisable to stop the boiler.
So I say:
Before releasing the pressure, check that the valve on the expansion tank is open. If it is closed, open it, the pressure should drop. If it was open, bleed it from the battery in any convenient place. Under no circumstances should you bleed off the pressure from the boiler safety group yourself - if a speck gets under the valve seat, it can be very difficult to wash it off - this is how the valve drips.
Victor:
Install an expansion tank and forget about pressure surges.
L@rchik:
Bleed the air from the heating radiators, the pressure will immediately drop. Do not interfere with a well-functioning mechanism (boiler).
What can lead to traffic jams in the circuit?
The importance of air vents cannot be overstated. Traffic jams in the circuit can lead to different processes:
- circulation disturbance;
- pressure surges;
- reduction in the efficiency of heating equipment;
- corrosion of metal.
Autonomous air vent
Installing an air vent in the heating system prevents the formation of plugs and pockets. When bumping into them, the coolant stops. Sometimes plugs cut off entire sections with radiators from the circuit. At the same time, the pressure in the system increases. When it reaches a critical level, an emergency release of coolant occurs. This, in turn, leads to a drop in pressure. At the same time, there are many cases when air collected in the batteries, the circuit continued to work, only half of the radiator became cold. This significantly reduces the heating efficiency and slightly increases the cost of its operation.
For open systems, one of the most serious threats is rust. At the same time, the question of how to remove air from the heating system arises only at the design stage. Such circuits are assembled at an angle from pipes with a large diameter, so there is a lot of water in the system. Considering the fact that the coolant is in contact with air and draws it into circulation, the oxygen level in the pipes is more than sufficient. Since it takes a long time to remove air from the heating system, oxygen reacts intensively with the metal. The result of the interaction is the formation of corrosion on the inner walls of the pipes. Rust sometimes eats up the tank so much that you have to replace it.
The direct consequences of traffic jams in the circuit entail indirect ones, which are no less dangerous:
Occurs if the valve for bleeding air from the heating system and all sensors are in good working order and working correctly. Due to the increase in pressure, an emergency release of the coolant occurs, which leads to a decrease in its quantity in the circuit. After cooling, there will not be enough fluid in the system, and the pressure will drop sharply. If it does not correspond to the minimum required to turn on the boiler, the heater will not turn on. And from this moment in winter, the countdown begins when the pipes defrost. Depends on how insulated the house is. Sometimes this happens in just three hours. In this case, unpleasant news awaits you at home from work;
This occurs if there is a malfunction of the valve for bleeding air from the heating system, or the temperature-controlling equipment. An unlikely situation, although possible. The results of this are very disastrous. At best, repair or replacement of the boiler; at worst, injury;
rupture of the circuit and release of the hot water fountain.
A very likely situation is that the joints may not be tightened enough. As the pressure increases, they cannot withstand and crack. At the same time, hot coolant flows from the pipe like a fountain. Not only does the circuit need to be repaired, but the neighbors also need to repair the ceiling, since you flooded it thoroughly. This is the kind of chain that can be caused by simply airing the system.
Monitoring normal pressure in the heating system of a private home and ways to normalize it
The operation of the heating system is characterized by several indicators. The main one is the current temperature regime, which depends on the parameters of the equipment and the pipeline layout. But in the process of heating and circulating water, internal pressure inevitably arises. The operational properties and integrity of the entire system depend on compliance with the normal value of this indicator.
What is the working pressure in the heating system
Pressure in the heating system occurs as a result of several factors. It characterizes the effect of the coolant on the internal walls of the elements (boiler, pipes, radiators). Until the water is filled, the pressure in the pipes will be equal to atmospheric pressure - 1 bar. But as soon as the process of filling water begins, this indicator begins to change.
Even with cold coolant, water pressure will be exerted on the pipeline. This is due to the different arrangement of the system elements - with an increase in height of 1 meter, 0.1 bar is added. This type of impact is called static. It is typical for open heating systems with natural circulation. Their design makes it possible to almost instantly stabilize possible deviations in the indicator.
Along with this, there are other reasons for the difference. Exceeding the normal value may be due to the following factors:
- Natural expansion of the coolant volume due to heating.
- Incorrect pipe diameters. The boiler outlet pipe must be the largest size. If this rule is not observed, then as the diameter decreases, the pressure increases.
- Increased power of the circulation pump or malfunctions in its operation. The result of the latter may be water hammer.
- An open tap for recharging the system from the water supply. This happens if the pressure in the water supply pipes exceeds that in the heating system.
The reason for the drop in the nominal pressure indicator can only be a leak. In some cases, this is a microcrack in the pipe or, most often, in the boiler heat exchanger.
Normal pressure readings
There are no pressure standards for autonomous heating systems. This value is calculated depending on the equipment parameters and pipe characteristics. In this case, it is necessary to follow the rule that the normal pressure in the heating must correspond to the minimum value of the “weakest” element.
The next factor is the required difference between the pressure in the forward and return pipes of the boiler. It should be 0.3-0.5 atm. This is one of the mechanisms for maintaining normal coolant circulation.
Average values are in the range from 1.5 to 2.5 Atm. , depending on the parameters of the entire heating system. The pressure calculation is carried out at the design stage and takes into account all factors - characteristics of equipment, components, number of floors of the house.
Ways to control and stabilize it
For visual monitoring of pressure, special devices are installed - pressure gauges.
Almost all modern heating boilers are equipped with this device. But, in addition to this, installation of additional measurement points is necessary. They should be located in the following sections of the pipeline:
- Inlet and outlet pipes of the heating device.
- The highest and lowest points of the system.
- In places where the main line branches, there are tees, three-way (two-way) valves, and manifolds.
However, they will be able to show critical changes, but will not affect the current situation in any way. Therefore, stabilization devices are additionally installed.
Normalization methods
By default, every closed heating system with forced circulation must be equipped with an expansion tank. This is a sealed steel structure, divided into 2 chambers (read more about choosing a tank here).
One of them is connected to the main line, and the second is filled with air. A rubber membrane is installed as a partition between them. The pressure in the upper chamber is normal. If water expands due to heating and pressure increases in the pipes, the membrane moves towards the air chamber, thereby compensating for the excess.
A more effective way of stabilization is to install a safety group, which includes a pressure gauge, an air vent and a safety valve.
Each of them performs its own function:
- The pressure gauge indicates the current pressure.
- The air vent is designed to prevent air locks.
- The safety valve is activated when the maximum pressure value is reached. Using a spring mechanism, the rod rises and excess water is removed from the line. This happens until the pressure stabilizes.
The safety valve can be installed separately in “problem” heating areas. It is important to provide a mechanism for discharging excess coolant into the sewerage system or into a storage tank.
All of the above pressure stabilization options are used for heating a private home. In addition to them, there are expensive automatic systems that can fully control all system parameters - temperature, pressure, timely addition of water, etc. But their purchase is not always advisable due to their high cost.
Source: https://dearhouse.ru/sistemy-otopleniya/davlenie-v-sisteme-otopleniya/
Optimal value for a private house or cottage
Any boiler operates at certain system settings, in particular, it is necessary to correctly calculate the water pressure. This value is influenced by the number of floors 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 five-story apartment building this value is 2-4 atm, and for a ten-story building it is 5-7 atm. For higher buildings, the pressure level is 7-10 atm, the maximum value is achieved in heating mains, here it is 12 atm.
For radiators that operate at different heights and at quite a decent distance from the boiler, constant pressure adjustment is required. In this case, special regulators are used to reduce it, and pumps to increase it. But the regulator must always be in good working order, otherwise sharp fluctuations and drops in coolant temperature will be observed in certain areas. The system must be adjusted so that the shut-off valves are never completely closed.
Control devices
To control the water pressure in the heating boiler and heating system, pressure gauges and thermomanometers are used. The latter are combined devices for monitoring two parameters at once. After starting the circuit, it is necessary to monitor the indicators so that they do not go beyond normal limits.
Some double-circuit floor-standing and wall-mounted boilers do not have traditional dial pressure gauges. Instead, electronic sensors are installed here, information from which is transmitted to the electronic unit, after which it is processed and displayed on the display. Another approach is also possible - if the heating unit does not have a pressure gauge, it is provided by the safety group.
The security group itself includes the following nodes:
- Pressure gauge or thermomanometer - for monitoring temperature and pressure in the heating circuit;
- Automatic air bleeder – prevents the circuit from becoming airy;
- Safety valve - relieves coolant pressure when it increases excessively.
Be sure to provide this unit in a closed heating system.
Causes of low or high pressure in the heating system
If you know what the pressure in the heating system should be, you can easily identify the problem. A drop in pressure can be caused by the following reasons:
- Leakage in the system. In most cases, this occurs at the junctions of system elements. It can also burst old and worn pipes. How do you know if the leak is in the pipe or the pumps? It is necessary to turn off the pumps and monitor the static pressure: if it drops, it means there is a leak in the pipeline. If the pressure is within normal limits, the cause should be sought in the pumps themselves. This is done like this: under pressure control, different sections are turned off one by one. Having discovered an area with low pressure, it is cut off from the system and repaired.
- Boiler malfunction. There may be several reasons: - Scale in the heat exchanger. This is a common occurrence in regions with high water hardness. The problem can be solved with the help of anti-scale additives. — Cracks in the heat exchanger due to wear or defects. In addition, due to water hammer, the bithermic heat exchanger may collapse. To fix the problem, the heat exchanger is either sealed or replaced with a new one.
The rise in pressure is caused by the following reasons:
- Incorrect pipe diameter. The largest diameter should be at the boiler outlet pipe. Ignoring this rule leads to the pressure in the system increasing. To solve this problem, you will have to change the pipes.
- Automation malfunction. If the calculation and installation of the automation was carried out incorrectly, the system will be constantly recharged and the pressure will increase. To fix the problem, you need to shut off one line and set up the automation.
- Airlock. It is necessary to bleed air through the expansion tank or air collector.
- Filter clogged. After cleaning, the pressure should return to normal.
To prevent this kind of trouble, you should check the equipment for leaks. Immediately after installation it is pressure tested. For prevention, it is necessary to clean the pipes from scale at least once every two to three years before the start of the heating season. If you are concerned about inconsistent pressure in your heating system, you should contact a qualified engineer. He will diagnose and troubleshoot problems using professional equipment.
We hope that you found our article useful. But if you want to learn more about the correct pressure in the heating system, contact the specialists of the Viessmann-partner heating equipment showroom.
How to bleed air from the boiler
Modern heat sources are equipped with automatic air ventilators or Mayevsky taps located in the upper part of the unit.
This design solution allows you to bleed air during operating mode without stopping the process of heating the room, just like with any radiator on which a similar valve is installed. To do this, periodically open and close the Mayevsky tap, with an interval of several minutes. The procedure is repeated until a hiss or whistle appears, indicating the release of the air lock. The appearance of sound requires holding the bleeder in the open position until the coolant appears.
The lack of special devices for removing plugs on the boiler requires the use of the same devices on pipelines located above the heat source.
The ideal conditions for freeing the air lock in the boiler is the possibility of separately shutting off the heat source circuit with the return pipe and circulation pump. When turned on, the coolant is pumped, and periodic opening of the Mayevsky tap or monitoring the operation of the automatic air vent by pressing the spool allows the blocked circuit to be released from the plug.
If there is no circulation pump in the closed circuit that cuts off the boiler with the return pipeline, then turn on the energy source: gas, electricity, and in the case of solid fuel, light the firebox. After heating the “supply” pipeline, the deaerator is periodically opened. The coolant, heating up, will rise from the boiler along the main line due to heating and return through the connecting pipeline - back to the heat exchanger. This technique requires careful monitoring of the temperature, especially when servicing a heat source other than solid fuel. The movement of coolant along such a circuit will be very slow and this is taken into account when performing work.
If it is not possible to shut off the boiler water circuit and there are air vent devices only in the upper part of the line, it is necessary to drain the coolant and then fill in the entire required volume of water. Before embarking on such global measures, it is recommended to turn off all devices (except the boiler) and, turning on the pump, release the pressure through the nearest air vent on the main line until sound or bubbles appear. The absence of a result indicates the need to completely drain the coolant.
