The pressure in the expansion tank of the gas boiler: the rules how to pump and adjust
One-circuit or two-circuit gas boiler. is the equipment that makes our life in a house or apartment more comfortable. Manufacturers now produce a huge range of gas appliances, differing in power, functionality, as well as method of installation. But even the most expensive and reliable models can fail. Agree that it is not very pleasant to be left on a winter evening without heat and hot water.
After analyzing the possible causes of failure of gas equipment, we have come to the conclusion that most often malfunctions occur due to the fact that the incorrect pressure in the expansion tank of the gas boiler or water heater. In the article let’s understand why an expansion tank is needed, how to pump air into it independently and set the optimal pressure.
Pressure in the heating system: what it should be and how to increase it if it drops
Following a pressure failure in the heating system comes a problem. the quality of space heating in the home is dropping. You can, of course, set the heating once and for a long time, but indefinitely this period will not be. One day the normal pressure in the heating system will change, and significantly.
We will tell you how to keep under control the physical indicators of the coolant. We will show you how to ensure that the water flows at a stable speed through the pipeline to the device. Understand how to obtain and maintain a comfortable temperature in the premises.
In the article proposed for review, the causes of pressure drop in the systems of closed and open type are described in detail. Effective methods of balancing are given. The presented information is supplemented with diagrams, step-by-step instructions, photos and video tutorials.
How to depressurize the boiler Baksi?
Gas boilers are used for heating and hot water in private homes by transferring heat from the combustion of gas through a system of pipes and radiators.
To provide warm water for all plumbing fixtures, heating walls and “warm floors” is enough for a two-circuit device.
To perform its functions, the boiler must maintain working pressure in the circuit. only under these conditions, the coolant will circulate normally and keep a comfortable temperature. If it decreases, precious heat is lost, and the unit itself can shut down and even fail.
Norms of pressure in the gas boiler
There is no common pressure standard for all domestic gas boilers. It is calculated based on the technical characteristics of the equipment and pipes that make up the heating system. However, there is a rule: the average operating rate should not exceed the minimum values of the most low-power components of the circuit.
Important! The necessary requirement for the working water circulation inside the boiler is also the difference between the pressures of forward and reverse flow of the coolant, which must be at least 0.3 atmospheres.
There is also a static pressure on the pipe system due to the differences in the placement of the components of the heat chain (each meter of height adds 0.1 bar).
On average, when fully heated, the pressure level in the system should be kept around 1.8 bar, and in the cold 1.5 bar.
Data on each specific model, including the maximum and minimum allowable values are in the instructions from the manufacturers. In this case, the pressure at the lower limit is allowed only at the stage of filling the circuit with coolant.
Home gas boiler equipment is equipped with pressure gauges to monitor the pressure level.
The main causes of pressure drop in the gas boiler
Normal pressure is necessary for the functioning of boilers, otherwise the water supply to the unit will shut down and it will shut down automatically. Therefore, when you see the first signs of falling pressure in the circuit to avoid emergency shutdown (especially unpleasant in winter), you should call a service technician or yourself to find out why the pressure in the gas boiler drops.
The most common causes of faults are as follows.
Turning on the hot water
When the gas boiler is first started, air is squeezed out of the system, starting with the boiler itself, which it leaves through automatic air vent valves. Experts explain this situation by the peculiarities of design of two-circuit boilers and believe that the pressure does not actually drop.
To ensure that the escaping air does not accumulate in the radiators, they should install taps Maevsky. When you unscrew it first with a hissing air comes out, then begins to drip a little water.
In wall-mounted models of boilers there is a screw on the pump, which allows you to remove the air. It should also be unscrewed and slightly clamped, such manipulation helps to increase the water pressure, after which the unit will function normally.
This is often a problem faced by owners of underfloor heating, which are many meters of pipes, where the coolant comes from the boiler. Therefore, at the first start-up and a couple of weeks after that may hiss and air coming out of the system through the automatic air vents, and the pressure in the system will be below normal.
The most frequent reason to call a master because of the drop in pressure in the boiler. leaks. It is good if it is in a prominent place, it can be quickly discovered by puddles of hot water and eliminated. But sometimes it’s very difficult to visualize, such as inside a radiant heat flooring system. In implicit cases, the refilled coolant “flies away” from the circuit, and the pressure in the system does not rise.
Determine the location of the breakdown can be made by passing a dry cloth over the entire accessible surface of the pipes, including joints, to inspect the walls for leaks. Previously you should disconnect the boiler from the heating system and drain the coolant. You can use the compressor to pump air through the system and by the sound to find the place of leakage. In the most difficult cases a thermal imaging camera will help.
A possible reason why the pressure drops in the gas boiler and without leaks. the formation of airlocks. They form due to:
- Incorrect filling of the heating system. a lot of air was present in the water. Experts recommend treating the coolant with a special device before pumping it into the circuit, otherwise air locks cannot be avoided;
- Poor sealing of joints of pipes and other elements of the system;
- Failure of valves to release air.
Further information. Air plugs cause noises and vibrations in the system, which leads to leaks and leakages. The coolant circulates inefficiently: the flow rate of gas will increase markedly, while the batteries will be slightly warm.
The problem with the expansion tank
Usually they begin a couple of months after the start of the heating circuit: no leaks, but the coolant escapes and the pressure in the faucets is discharged. The problem is that the pressure in the expansion tank of a two-circuit boiler, separated from the other part of the boiler by an elastic membrane, decreases due to bleeding of air through the nipple on the top of the unit. As a result, the entire expansion tank is filled with water from the circuit under the pressure of the coolant. When the pressure rises further, there is nothing to bleed, so a safety valve reset coolant.
Note! If the problem is not eliminated, there may be a complete rupture of the membrane of the expansion tank, which will require its replacement.
Malfunction of measuring equipment
In cases when there are no visible or detectable leaks, tightness in the system is not broken, the expansion tank is intact, and the pressure in the boiler constantly increases, you should call specialists and check the performance of the boiler automation or manometer. This equipment may also malfunction and give incorrect readings. In such a case there is nothing else to do but replace the gauge with a new one.
Cracks on the heat exchanger in the boiler
With long-term operation of the gas boiler, constant flushing with caustic reagents, poor workmanship of parts, as well as periodic emergency water hammer, microscopic cracks appear on the heat exchangers. The coolant leaks from the circuit through them. When the gas is turned on, such cracks can drain and evaporate all the moisture from the heat exchanger and combustion chamber.
It is possible to determine the localization of the problem by the presence of scale. Microcracks on the conventional heat exchanger can be soldered, and the bithermal will have to be replaced.
Heat carrier drain valve is not closed tightly
One of the easiest and most trivial reasons for which the pressure in the heating circuit can gradually drop is a loose and screwed tap.
Other possible causes
There are also a number of other nuances that lead to insufficient pressure in the heating system. This:
- Leaks of heat carrier at the joints of pipelines;
- Metal damage to the elements of the heating system by rust;
- Low-quality heating installation;
- Improper functioning of the boiler automation.
Ways to increase the pressure in the boiler
This problem is solved in different ways, depending on what caused it.
In the case of leaks detected visually or by thermal imaging, the problem is eliminated by tightening or sealing the connection or complete replacement of the node.
Please note! Before pumping the pressure in case of a rupture in the boiler expansion tank or injuring the nipple, this element must be replaced with a new one. In difficult situations you have to replace the tank itself.
Cracks in the heat exchange elements of the boiler are visualized by long-term observation or with the help of specialists, after which it is necessary to seal the damaged area of the circuit.
To eliminate air s in the system, you must turn off the heater, open the valve on the Mayevsky valve and bleed all the air, then you should add coolant to normalize the pressure in the system. All bubbling noises should disappear.
If the valve on the heating medium outlet is open, it must be turned until it is completely closed after checking the tightness of the wedge.
Difficult situation happens when the pressure drops in the heating circuit, located inside the walls, the pipes are firmly embedded into the frame of the building. Therefore, for such designs it is better to choose durable and reliable materials.
Further Information. When carrying out repairs, you must objectively assess your technical knowledge and in difficult situations call on professionals.
How to reduce the pressure in the boiler
You may also have a question, how to release excessive pressure in the gas boiler, because the constant increase provokes emergency shutdowns, and it can lead to failure of the boiler. The pressure can be reduced by means of a Maevsky cock. It is also necessary to check and fix the make-up valve or a secondary heat exchanger.
To prevent an increase in pressure in the circuit can install a brass safety group for 3-4 bar. We recommend adding corrosion inhibitors to heaters to eliminate clogged filters.
Prevention of airlock formation
It is necessary to follow the mandatory rules:
- Properly install the piping and connect the boilers,
- Pre-check the equipment before the final start-up;
- Treat the coolant before loading it into the system.
This manufacturer has a bypass element, which allows you to solve the question of how to raise the pressure in the boiler Ariston in case of power outage.
It allows you to reduce unnecessary heating of the heat exchanger due to insufficient water flow. The flow of the coolant in the system is started, bypassing the circulating pump.
The minimum pressure at these boilers half a bar, in case of its insufficiency on the boiler screen causes errors E40 and E41. It can be regulated by a tire pump, because the valve on Baksi boilers is an ordinary car nipple.
Note! At the first start of the coolant in the system, the boiler can display error E10, it passes automatically.
These Korean boilers are structurally designed for pressure drop up to 0.1 bar, which minimizes emergency blockages. Such units are ideal for high-rise buildings. The boiler is equipped with a system of nozzles, safety systems and feeding devices that allow it to operate at a reduced pressure of up to 4 mbar. You can regulate the pressure with a remote control.
Tips and recommendations for regulating the pressure in the gas boiler
Be sure to make sure that the system is airtight before you raise the pressure in the gas boilers. To do this, inspect all heating appliances, pipes, fittings, circulating pumps.
Experts also advise to carefully control the upper pressure limit in the system. it should not exceed three atmospheres.
Adding pressure to the tank is possible with normal air with an auto pump with a manometer.
Pay attention! To prevent the formation of air s, it is necessary to correctly select the model of the boiler for the room, coordinating the possible areas for heating and power of the unit.
Any private home must be heated and supplied with hot water. In modern construction, gas boilers are used for this purpose. For their normal operation requires optimal pressure, which for several reasons can drop, leading to a stoppage of the boiler. A knowledgeable owner should know how to raise it, or seek professional help.
How to reduce the pressure in the boiler Baxi?
Standard operating pressure in closed heating systems with forced circulation is the value in the range of 1.5-2 bar. If the pressure in the gas boiler drops, the work as a heating circuit, and DHW circuit becomes very difficult or impossible, automation of some models suspend the boiler.
There are many reasons why it happens, but to diagnose them yourself is not difficult. In this article we will consider all the possible causes, in descending order of probability, as well as identify what should or should not be done in each case, and how to raise the pressure in the gas boiler.
Standards and methods of control
First, let’s briefly consider the types of pressure and how to measure it, which will help you better understand how it is formed in the heating circuit and the circuit of hot water (DHW).
Types of pressure and its norms in the gas boiler
As in the single-circuit and two-circuit heating systems, the pressure is:
- Static is the natural pressure created by gravity acting on the coolant (each meter of height of the system riser creates about 0.1 bar);
- dynamic. artificial pressure created by force in a closed loop (by pump or heated coolant expansion), depends on the parameters of the pump, the coolant temperature and tightness of the system.
- Operating. the real pressure (static dynamic), it is measured by instrumentation, the normal value is 1.5 or 2 bar;
- maximum. the maximum allowable for the system, even a brief exceedance of it (water hammer) with a high probability may lead to emergency depressurization of the system (in other words the rupture of pipes, radiators or heat exchanger of the boiler).
How it is measured
Most models of wall and floor gas boilers have a built-in pressure gauge that measures the operating water pressure in the heating circuit. But even if you have one, we recommend installing an additional one: as part of the safety group (pressure gauge/thermometer, safety valve, bleeder valve).
Combi Boiler Too Much Pressure. How to reduce the water pressure. Central Heating
The fact is that even an arrow factory pressure gauge can fail over time and measure pressure incorrectly or show pressure spikes, not to mention electronic gauges. Additional control and measuring device installed on the boiler feed will quickly check and compare the readings to immediately eliminate the main pressure gauge malfunction.
Faulty make-up valve (fill)
Location of make-up valve in wall mounted gas boilers. For the exact location of the valve in your model, check the instruction manual.
The most common, known to many owners of two-circuit models, especially with plastic, unreliable make-up valve. It may be loose or defective.
Then the heating circuit communicates with the water system, where the pressure is usually higher, there is a pressure equalization between the two systems. However, as soon as you open the hot water tap, the pressure drops quickly.
Decrease observed only with DHW, this is a sign of the defect, as soon as the hot water tap is closed, the pressure is restored sharply to its previous values.
Faulty make-up valve is not only dangerous to possible malfunction of the system, but also leads to increased oxidation of the inner surface of the pipes, rapid deposition of salts inside the pipes and boiler coil heat exchanger coil, subsequently leading to complete clogging.
Check fittings most carefully.
Leaks can be not only through the make-up valve, but also in the joints of pipes and fittings, radiators, expansion tank. Therefore, if the low pressure during the operation of the boiler is always observed, not only when using DHW, it is necessary to check the entire system for leaks. It is necessary to remove the front cover of the boiler, check all the nodes inside the boiler, even if the water is not dripping from the closed boiler unit.
Usually the system is checked for leaks before the heating season, but we can not exclude the wear of gaskets and seals, possible metal corrosion, loosening of connecting fittings, etc.д. During operation of the heating system.
The presence of air s
The cause of blowing air in the system can be many factors: sucking air through the leaky areas, improper filling of the circuit with the coolant and putting it into operation, high water temperature (above 85-90 ° C), which leads to high air emissions. A characteristic feature of air tightness is often an interruption of heat transfer in any part of the system (after the air lock).
Nevertheless, the problem is easily solved. It is sufficient to bleed air through the drain valve of the safety group or the Maevsky valve on the radiators.
Problems with the expansion tank
The pressure in the expansion tank of the gas boiler corresponds to the pressure in the whole system and depends on the boiler model. Normal operating values, as we said earlier, are values of 1.5-2 bar. Some models operate normally at 1-1,2 bar.
Inside the closed expansion vessels are divided into two compartments: water and air. They are divided by a special membrane, which bends when the coolant expands, increasing the volume of the chamber for the coolant and reducing the volume of the chamber for air. But in order to initially, when starting the system, to set the membrane in the proper position and to adjust the pressure in the system, air is pumped into the tank through the nipple from above.
Over time, it can leak and when the coolant expands, it can bleed air from the expansion tank chamber, which causes the membrane not to be pressurized, the tank does not hold the optimal pressure.
To replace the nipple usually impossible separately, so you need to replace the entire tank. Before you do this, make sure that the rest of the system is tight and the air is bled through the nipple of the expansion tank. Price of the problem: 1 500-6 000
Cracks on the heat exchanger
Microcracks on the heat exchanger is difficult to see, the more so that the water seeping out quickly evaporates and dries out in a high temperature element. In many models of wall mounted boilers, the heat exchanger is located in a closed combustion chamber, it can be accessed by removing its front cover.
If the water pressure drops in a two-circuit gas boiler, do not forget to pay attention to the secondary heat exchanger, it is located next to the primary. Some models are equipped with a bi-thermal heat exchanger, which is a single element. Minor depressurization is resolved by patching or welding damages, and in case of serious leaks the heat exchanger will have to be replaced.
Defective relief valve
Principle of operation of the spring loaded safety valve for the individual heating system.
Resetting (safety) valve is part of the group of security or installed separately, it is necessary to bleed excessive pressure in the heating system.
The principle of its work is the following: the spring presses on the valve, which blocks the coolant flow, but as soon as the pressure exceeds the allowable limits, the spring compresses, opening the valve and the release of excess air or coolant.
After 7-10 cycles, spring reset valves fail due to wear of the spring, which no longer holds the same pressure: it jumps or declines. At the same time there is a constant leakage.
Dismantle and repair the relief valve yourself is not strongly recommended, it is better to just replace the mechanism. Price of the issue is only 500-900
Improper operation of control and measuring instruments
If all the previous possible causes are not detected, it could be the pressure gauge. Sometimes the problem can be detected when the pressure according to the gauge has dropped to 0, which is rarely the case due to at least the static pressure of the heating medium. The best way out, as we wrote earlier, is to install an additional pressure gauge on the boiler supply. If this has not been made, it is difficult to diagnose the problem yourself, it is necessary to call a master.
Pressure constantly jumps in a new gas boiler after initial start-up
If the pressure is constantly changing at the first start of the equipment. it is normal, there may be a sufficient amount of air masses in the circuit, which in the presence of appropriate drain valves will soon come out and indicators will normalize.
Unexpected rise and fall of pressure: causes and solutions
It is not difficult to find out what the pressure should be in a two-circuit boiler. this information is publicly available. But finding the cause of incorrect values is more difficult. Let’s look at a few common causes.
An increase in pressure in the system
There are many reasons for a sudden drop in pressure:
- The temperature of the heating medium has increased due to a rise in temperature;
- The coolant due to a system malfunction or other reason has stopped moving through the circuit;
- The system is clogged or there is an air lock in the system;
- you or someone else has accidentally closed the gate valve;
- Were mistakes during installation;
- The boiler output is set too high or there is a malfunction of the pump.
In modern boilers installed expansion vessels, which offset the expansion of the coolant during heating. There are also safety valves that protect the circuit from damage due to high pressure or even a water hammer. If you see that the pressure values are close to critical, try to reduce the boiler output. If the situation does not return to normal, call a service technician. He will find the problem and fix it.
Pressure drop in the system
This often occurs when individual elements of the system are worn out. Microcracks appear, ruptured pipes, rubber membranes in the expansion tank are damaged. You can try to find the leak yourself. The most “problematic” places. these are the joints of pipes, connection points with batteries, etc. д. If you find a leak, this is the reason for the pressure drop. It is much harder to find leaks if the pipes are hidden in floors or walls. Here without the help of a wizard can not do, because unknowingly you can in search of leaks disassemble the coating where it is not necessary to do this. You will have to spend extra money for repairs.
How to release the pressure in the gas boiler: problems, elimination, prevention
Hello, dear readers and visitors to ballony.com.ua. Often owners do not know how to release the pressure in the gas boiler, do not take prompt action in time. As a result of malfunctions lead to total failure of equipment and gross violations of safety rules. Therefore it is necessary to know the causes of pressure increase and ways to reduce it.
Increased pressure in the gas boiler leads to various problems. The most terrible is the explosion of equipment. Therefore it is necessary to regularly monitor the state of the equipment and the indicators of the manometer. For models of different brands have their own standards, which should not be exceeded.
Problems and troubleshooting
Difficulties arise in different ways, and measures are taken according to the situation. The list of problems and necessary actions are as follows:
First. The membrane of the expansion tank is damaged.
When the water in the heating network is heated to the maximum parameter, it increases in volume by 3-4%. In this state, the liquid ends up in the expansion tank, so it compensates the pressure in the network.
If the diaphragm is damaged, it fills the volume completely and the head in the network is reduced. When the make-up valve is opened and the fluid is added to the system and its temperature rises at the same time, a higher than normal head is formed.
How to detect membrane breakage? The following signs appear:
Measures. replacement of the membrane or the entire expansion tank.
The second. this tank has a rather modest volume. Because of this, the pressure is rapidly developing with an increase in temperature. The capacity is determined by the heat generator capacity taking into account the connected domestic radiators. If instead there are pipes, the amount of heat carrier significantly increases, and excessive pressure is guaranteed.
In this case it is necessary to replace the expansion tank with a more voluminous version.
Third. the head in the compensating tank does not correspond to the nominal. To correct the situation you will need a car pump and a manometer.
Pumping is performed, but the water is previously drained from the boiler, and two valves are blocked: the supply and return.
It is necessary to pump until the water stops flowing. The air is then vented and re-inflated to the parameter indicated in the boiler document. Some manufacturers do not show in the manuals the pressure rating of this tank. This is a sin, for example Immergaz.
Fourth, a hydraulic attack. The problem is more typical of two-circuit models in which the expansion tank is located immediately behind the circulation pump. And when it is turned on, the pressure rises quickly and then drops exactly in the same way.
Corrective action: install an expansion vessel on the return pipe. The pump itself should be located after it, in front of the boiler.
Fifth. air lock in the heating sector.
- Filling this circuit with water too quickly. This process should go slowly. In this case, open the valves that deflate. They close until there is no water dripping from the upper edge.
- Maevsky cocks are broken. They need to be replaced.
- Loose pump impeller. It is adjusted.
Sixth. shut-off valves are weakly open or closed. The pressure in the water supply stream increases, the apparatus is blocked.
Remedy: valves are opened to their limit, check shut-off valves for leakage.
Seventh- contamination of strainer and sludge collector. It is washed thoroughly or replaced.
Eighth. the make-up valve is defective and leaks.
Water in the pipeline in which the pressure is in the range of 2.5. 3.5 bar, goes to the heating sector where the pressure is less. Because of this, the pressure in this sector increases.
Remedy: Replacement of valve or worn gasket.
Ninth: Automation failure, thermostat or controller malfunction. The causes are identified only by experts.
It is possible to eliminate the dilemma with your own hands, if a certain error is reflected and the method of its elimination is specified in the manual.
Hot water with a serious head ends up in this fistula and develops pressure in it.
Exit: solder the heat exchanger if technically possible. If not, replace it with.
Compensation tank of different modifications of boilers has its own value of pressure. And these parameters are presented in the following table.
|Model||Pressure rating for the expansion tank (bar)|
Pressure in isolated heating networks
These networks have a dynamic pressure, which is created by a special pump. Due to what they have such advantages:
- The length of the heating chamber develops in direct proportion to the capacity of the pump used.
- Both parallel and series connection of batteries is allowed. Heat dispersion is more uniform in the first case.
- It is possible to mount pipes with small diameter.
- Due to the high dynamics of the coolant is better to save fuel.
- For the discharge of excessive pressure is enough to reduce the capacity of the pump.
- According to the length of the circuit and the diameter of pipes is easy to select the pump to relieve the pressure.
To keep the boiler in good condition and avoid excessive pressure, regularly:
- Check that the equipment safety group is in good working order. It consists of: pressure gauge, air diverter and safety valve.
- Add coolant (antifreeze) to the coolant. Carefully study the manual, because this is not allowed in all models of boilers. Due to this measure will be less clogging of the filter, reduce the amount of scale on the air diverters, and will not stick components defense valve.
- Flush the heat exchanger. This way develops its operating life, and it will not have fistulas and scaling on it.
Increase of pressure in the heating circuit
What to do if the pressure in the heating system increases too much?
First of all, you need to establish the cause, and there may be several:
- Improper filling of the circuit, its suffocation. Due to the rapid filling of the heating circuit airlocks can form in it. To avoid this phenomenon, fill the heating circuit slowly when starting it up.
- Temperature in the circuit is too high. Any increase in temperature and coolant leads to its expansion and an increase in pressure in the system. It is necessary not to allow too much increase, in order to protect the heating equipment from critical loads.
- Stopping the flow of the coolant. This can be caused by blocked shut-off valves, clogged strainer, airlocks.
To identify the problem area, you need to examine the entire circuit step by step.
Leaks can be caused by a makeup valve failure. valve gasket wear, mechanical damage to parts, scale caught between the seat and gasket. If the tap passes, the extra water coming from the water supply system to the heating main, increasing the pressure in it, because the pressure in the pipeline HTW is always higher. You need to turn the tap or replace it if it is out of order.
Air s are a common cause of heating system problems. They can lead to malfunctions of the gas boiler itself, and problems in the circuit or improper start heating.
To correct the problem will help restart the system. its slow filling of the coolant, starting from the lowest point, until from the highest point of the circuit water flows. All air vent valves must be open. Air s in the system can cause both high and low pressures.
The main causes of pressure drop
Common reasons why the pressure in the heating gas boiler drops, are:
- The coolant is leaking. Damage to the heating line leads to leaks, loss of heating water and decreased head.
- Cracks in the heat exchanger. Leaks in the boiler itself lead not only to a drop in pressure, but can also provoke more serious damage to the equipment, damage the electronics.
- Diaphragm rupture in the expansion tank. Through damage in the rubber baffle, fluid enters the air compartment and the pressure in the circuit is reduced.
To determine the location of the leak in the system, it is recharged to normal pressure and stop the circulation pump. Step by step, you need to examine the main line, establish the problem area and troubleshoot.
Pressure in the gas boiler grows causes
The pressure in the heating system should be normal. 1,5. 2,0 atmospheres for private houses up to 2 floors. If the pressure differs from the specified limits, the system must be “treated”.
In this article we will analyze the nuances of the heating system and boiler equipment. Let’s define what pressure must be maintained, how to set it, what it depends on The material above will probably help readers in matters related to the efficiency of the heating system and the use of equipment.