Why does the pressure in the gas boiler drop or grow: the causes of the pressure of the pressure method of preventing problems
Work to ensure the proper functioning of heating equipment does not end on its installation. Service requires a certain level of knowledge from the owner and constant monitoring the state of the system. It is important to understand why the pressure in the gas boiler drops or grows, which is why the equipment functions with changes.
The article presented by us describes in detail all the reasons for the instability of pressure in the system of preparation of the coolant and hot water. We will talk about how to eliminate problems and maintain indicators in the normal range. Our recommendations will help to cope with planning breakdowns and prevent failures in work.
Types of pressure in heating systems
Depending on the current principle of movement of the coolant in the circuit heat pipeline, in heating systems, static or dynamic pressure plays the main role.
Static pressure, also called gravitational, develops due to the force of attraction of our planet. The higher the water rises along the contour, the stronger its weight presses on the walls of the pipes.

When lifting the coolant to a height of 10 meters, static pressure will be 1 bar (0.981 atmosphere). An open heating system is designed for static pressure, its largest value is about 1.52 bar (1.5 atmospheres).
The water in the heating contours of the gravitational type moves due to the difference in the densities of heated and cooled water. When installing the boiler below heating devices, the circulation pressure increases
Heating circuits with the natural movement of the coolant are small in pressure. Its excess along with the excess of the coolant is dumped through the open surface of the expansion tank
The problems of insufficient pressure for the movement of the coolant are solved by installing circulation pumps
The use of the pump allows you to use a pipe system of smaller diameters in the structure of the system, t.to. Hydraulic resistance is overcome using the installed unit
The heating systems of the forced type arranged now are equipped with a closed expansion tank that provides the space of the coolant during its expansion when heated
The expansion tank in the pump heating circuit is regarded as a starting point in which the pressure developed by the pump changes the discharge value to the suction
In pumping heating systems with a closed tank, a safety valve of pressure is required to normalize the excess of the excess of the coolant into the sewer
Dynamic pressure in the heating circuit develops artificially. using an electric pump. As a rule, closed heating systems are designed for dynamic pressure, the contour of which is formed by pipes of much smaller diameter than in open heating systems.
The normal value of dynamic pressure in the closed heating system is 2.4 bar or 2.36 atmospheres.
Question answer
How to prevent a drop in pressure in the heating system?
The best measure is the annual maintenance of the boiler with cleaning and checking all nodes and pumping pressure in an expansion tank. When hot water is turned on, the temperature of the coolant in the dual.circuit boiler drops. Almost always the fault of the tap tile, it can be loosely closed or failed and misses water.
There is a difference in searching for faults in gas and electric boilers?
There are no fundamental differences. The sequence of verification is approximately the same. The main thing is to initially figure out under what conditions the pressure in the system decreases and choose the right option from the article.
In the open heating system in the winter, when the temperature of the coolant is high, it is necessary to add water much more often, this is normal?
Yes, this is the norm. The stronger the water heats up, the faster it evaporates.
Is it worth it to repair the boiler yourself if there is no desired tool and experience in this area?
It is worth repairing equipment only if there is confidence in the correctness of the work performed and there is no risk of flooding the house. The network has detailed instructions for boilers, wylant, etc.D.
Why did the pressure fall after replacing the radiators?
You need to know the following. After the installation of new aluminum batteries, the first time due to the reaction in the system water will decompose into oxygen and hydrogen, forming an oxide film. The problem will disappear after the oxidation of all the inner surfaces of the batteries.
If you follow the tips, identify the reason for reducing pressure in the system can almost always independently independently. If this was not possible, it is better to call a specialist.
the main reasons why the pressure in the heating system drops
The main reasons that the pressure in the closed heating system drops is:
- the formation of an air bubble in the heat pipeline or in a radiator;
- depressurization in the system of pipes and radiators;
- the failure of the heating boiler or circulation pump;
- the flow of oxidation reaction in aluminum radiators;
- violation in the functioning of an expander that is not able to cope with the role of the compensator and regulator of the established pressure.
If in one case, the repair and normalization of the working regime does not take much time, then, if another malfunction is detected, a serious constructive intervention may be required.
Air cork formation
The occurrence of an air traffic jam can lead to the following deviations in its debugged work:
- the drop in the pressure in the closed heating system and, therefore, the reduction in the speed of the coolant;
- the occurrence of noise and vibration during the progress of the coolant through the circuit leading to the weakening of pipe joints and welds;
- reduction in the service life of the metal parts of the system, due to the occurrence of corrosion.
The air mass can enter the system in conjunction with the coolant (water) or under the influence of other abnormal factors:
- prolonged simple house heating;
- The slope of the installed pipes is made incorrectly;
- reduced pressure in the heating circuit;
- unprofessional sealing of various compounds;
- repair work in heating devices and others.
To eliminate air plugs, when designing modern heating structures in individual construction, as a rule, they provide for the installation of several air separators (Maevsky crane). They are located in certain places along the entire chain (on radiators, on the constipation of boilers, on risers) and, when one of them is opened, there is an air bubble in a certain area.
The elimination of the air is carried out in the following order: identifying a plot with an air. unscrewing the Maevsky crane in this zone, air tanning along with a certain amount of water (in a pre.prepared basin).
Coarler leak
The most likely root cause of the fact that the pressure falls in the heating system of a private house is most often the formation of leaks. Water flow seeps at joints or taps.
It is necessary to turn off the pumps and measure the pressure indicator in static mode. Its fall is observed. the heat carrier leak is present. The testimony has not changed. the cause of the malfunction lies in another place.
The leak, as a rule, is easily sought out in the wake of water on the floor or walls, corrosion formations on pipes or radiators.
The use of this method may not bring results when using plastic pipes in the design. Then, for effective search, it is recommended to use the thermal imager or the test using high air pressure. These methods involve the involvement of qualified specialists in this field and special equipment.
The identified leak is eliminated by one of the available methods:
- replacement of the damaged section of the pipe;
- replacement, failed, sealing (FUM tape);
- enhanced screwing of weakened compounds.
Damage to the circulation pump or boiler
To identify a faulty pump, it is necessary to make all of them all, each time fixing the readings established during the device, manometers.
With long.term operation of the hydraulic pumps, the seals installed on them are exposed to wear and are subject to periodic replacement.
The suction of the pump can be clogged with mechanical impurities from the coolant. In this case, he is subjected to cleaning and, in order to avoid a repetition of a freelance situation, is endowed with a protective filter.
The root cause of the problem may be a wall boiler, in particular, its built.in heat exchanger. This may be the initial factory marriage, the appearance of a microcrack or obstruction of the tube, due to the scraped scale, the occasion of failure can be any, but the repair will be serious
The use of aluminum radiators
Aluminum radiator
One of the serious drawbacks of an aluminum radiator is increased gas formation when interacting with a water flow. Water, entering into a chemical reaction with aluminum, causes its oxidation, as a result of which hydrogen is released. This process actively proceeds in the new device. After a certain period of time, the oxidation reaction calms down and gas release stops.
Explanatory tank problem
Extending tanks used in heating structures are a cylinder or membrane device. In both cases, the metal tank is equipped with an internal rubber part: horizontal or bag.shaped membrane. With a long period of operation, it is covered with microcracks, rubber is subjected to deformation. This distortion entails a change in the percentage of two adjacent chambers and, as a result, a failure in the work of the entire system.
How to fix some common problems with your boiler
The problem with the expansion tank is solved by replacing its parts that failed, or entirely the entire device.
Incorrect calculation of the required volume of the expansion tank is also able to lead to the fact that the working pressure inside the heating system decreases. This volume must be calculated taking into account the effectiveness of the selected model and the coefficient of thermal expansion. The insufficient size of the expander leads to an excess of water, and, in this regard, the pressure in the heating system constantly drops.
If a decrease in pressure in the heating chain is caused by the formation of air constipation, then almost everyone is able to cope with a shortage on their own. If not, then experts do not recommend trying to deal with the problem on their own. A qualified specialist who owns professional skills will be able to quickly localize and eliminate the problem.
How to avoid air entering the heating system
It is very difficult to completely avoid getting into the air system, but you can minimize the problem and learn how to easily and quickly eliminate traffic jams:
- It is necessary to monitor the serviceability and tightness of all joints, shut.off valves, etc. D.
- Before starting the system, it is pumped into it with a compressor under pressure by 20 % more than working. Measurements from the pressure gauge are removed at the beginning of the dough and after 20 minutes. If the indicator has not changed, there is no leakage, the system is sealed. The arrow of the manometer, as well as a characteristic whistle, will say about the leak. To finally make sure that the leakage place was found, it is lubricated with a thick soap solution.
- Fill the system with cold water and smoothly. After filling, the air is lowered several times using air vents and crane cranes. Each time after descent into the system, water is added.
- It is recommended to use stainless or bimetallic heating radiators.
- It is also advised not to change the coolant too often. In a fresh portion of water, there are always impurities of oxygen.
- To describe the air, install air vents in all problem areas and regularly use them. Or supply radiators with automatic devices and monitor their serviceability.
The adaptive period of the system, during which you need to again and again lower the air and add water. several days.
The most frequent malfunctions and elimination of problems in the work of the boiler
With its functionality and electronics, there are certain disadvantages and malfunctions that can be encountered during the operation of the Navien Ace boiler.

Most often, users are faced with a problem when the unit stops working, and electronics gives a signal about a critical error. This situation can be caused by various factors, including sensors sensitivity. The most common mistakes:
Smoke removal. Fault code “10” indicates problems with the removal of combustion products. Possible reasons: a turbine malfunction, the pressure sensor is incorrectly attached, a chimney was closed, too long a pipe.
If this reason is not revealed, and the Navien Ace boiler continues to signal the error, then the cause may be ordinary gusts of wind. You can solve this problem by converting the chimney. As an option of operational response, you can open the boiler housing and disconnect the air supply hose. However, this measure is temporary.About frequent errors on the Navien gas boiler, see this
Important! The manufacturer recommends mounting boilers, provided that the chimney leaves the leeward side
- Flame sensor failure. The malfunction code “03” can talk about poor gas quality. The problem can only be solved by exclusion. First of all, the purity of gas supply nozzles is checked. If they are in order, you need to choose the optimal position of the controller electrode (it should be in the hot phase of the flame).
- Overheating of equipment. Malfunction code “01”. The possible reason is the blockage of the heating system, the circulation pump or a decrease in the duct. Ways to solve the problem: check the system and filter for air, check the serviceability of the pump and resistance of the coil for the closure, check the impeller in the circulation pump.
- Navien gas boiler, there is heating, but no hot water. Error code “02”. A jump in water temperature is observed on the remote control (it increases sharply to the maximum and instantly falls). Perhaps the cork has formed in the hot water supply system. The reasons can be: lack of pressure in the water supply, the dummy of the system, the circulation pump cannot gain momentum, the distribution valve is blocked or the duct controller does not work. To eliminate this malfunction, first of all, it is necessary to adjust the pressure, lower the air in the system, check the resistance of the pump coil and impeller for damage, open the boiler camshaft, disassemble the control of the regulator and clean the box.
In addition, when the hot water is turned on, the Navien boiler can buzz or make an incomprehensible noise. At the same time, there is no error information on the display and the pressure is normal. As a rule, this is due to the clogging of the heat exchanger. In order to eliminate the problem, you can clean the heat exchanger or replace it.
Did you know? It is best to choose boilers that are equipped with smooth adjustment. this will change performance depending on the air temperature.
Navien Ace gas boilers have high quality indicators and reliability in work. However, the duration and features of operation depend on how to correctly install and configure the Navien Ace boiler, as well as on the quality of the fuel used.
Why does my boiler keep dropping pressure?
Optimal value for a private house or cottage
Any boiler works with certain system settings, in particular, it is necessary to correctly calculate the water pressure. This value is affected by the number of storeys of the building, the type of system, the number of radiators and the total length of the pipes. Typically, for a private house, the pressure level is 1.5-2 atm, but for an apartment five-story building, such a value is 2-4 atm, and for ten-storytakes-5-7 atm. For higher buildings, the pressure level is 7-10 atm, the maximum value is achieved in the heating mains, here it is equal to 12 atm.
For radiators that work at different heights and a fairly decent distance from the boiler, a constant adjustment of pressure requires. In this case, special regulators are used to reduce, to increase. pumps. But the regulator should always be serviceable, otherwise, sharp fluctuations will be observed in certain areas, the drop in the temperature of the coolant will. The adjustment of the system must be carried out so that the locking reinforcement is never completely blocked.
What to do when gas pressure disappears?
The drop in gas pressure can occur for the following reasons:
- Increasing the load on the gas line on severe frosts and holidays, connecting additional consumers to the highway. Contact the gas service with a request to increase the pressure of gas.
- The gas filter clogged. clean the filter.
- The gas hose clogged. Change the new one.
- The nozzles clogged. Clean them using a brush.
- The gas valve is faulty. If the situation does not change after its disassembly and cleaning, replace it with a new.
- Old pipes on the gas highway rusted. There is a leak. inform the gas service.
What to do if the gas supply problem occurs constantly. some users connect a gas cylinder between a gas pipeline pipe and a boiler using it as a receiver.In this case, when the unit is turned on, the gas will come directly from the cylinder, without creating a vacuum in the gas pipeline.

There are models of units, for example, Buderus, Bosch, Deo (Daewoo), which work at low pressure, when buying a boiler, you should pay attention to this.

Another solution to the problem is to replace the gas with an electric boiler. Its use will be undoubtedly more expensive, but you will be with warm and hot water constantly. Below are the values of gas pressure on the supply of some models.
Questions and answers
I often hear gurgling sounds in an expansion tank, after which the pressure on the pressure gauge drops a little. After the time when the boiler turns on, the pressure is aligned. What could be the reason?
You need to check the expansion tank for performance. To do this, you need to pump a pump with fixing the data of its pressure. If for some reason he does not keep pressure even in the absence of water, you will need to replace.
When there is severe frosts outside, I add water to the tank every 3-4 days. She evaporates so quickly or you need to look for another reason?
If the pressure on the pressure gauge drops and the system is not enough fluid, you need to look for a leak. Perhaps these are small holes, water from which immediately evaporates, so you do not see the expected puddles. Check all the joints and radiators, after which the expansion tank itself is dedicated.
The pressure on the pressure gauge drops sharply when I open hot water. Double.circuit boiler. The temperature in batteries immediately decreases. What is the reason?
Such signs indicate the descent of water from the system to the central water supply. Check if the fuel tap is closed and whether it is working.