Grows pressure in the boiler. Copper gas wall double-circuit. Repair Part 2

Hello, dear visitors! We continue to consider such a problem when the pressure in the dual-circuit boiler does not correspond to the norm.

In the last note on the same topic, the reasons for which in the two-circuit boiler is not stable, it falls, it grows. Or for example, it changes after turning on / off the DHW and so on, in general, if the pressure you have some way jumps, then feel free to go to this article, it is just for these cases.

And in this article, it came to core to find out the reasons why the pressure in the boiler is constantly growing. Only up! And it will grow until the safety valve of pressure emergency discharge will work.

Considering that the principle of operation of most boilers is similar, then this malfunction can manifest itself in various models. But, I will tell on the example of the ARISTON CLAS 24 FF boiler since the boiler is this model used by me.

Pressure in the boiler slowly falls, it is necessary to periodically add water to the boiler.

First consider cases when pressure drops all the time. This is a fairly frequent problem. it manifests itself in the fact that the pressure in the heating system is slow, sometimes within a few days / week decreases.

There are two reasons why this can happen:


The first is associated with the leakage of the coolant from the system, consider than it is dangerous and how to seek leakage. The second will be associated with the expansion tank, but there is a whole bouquet, not only a pressure reduction

The main reasons for dropping pressure in the gas boiler

Normal pressure is necessary for the functioning of boilers, otherwise water supply to the unit will turn off and it will turn off automatically. Therefore, when the first signs of its falling on the circuit is found in order to avoid emergency shutdown (especially unpleasant in winter), you should call a service wizard or find out why the pressure in the gas boiler falls.

Most often the causes of troubleshooting.

Turning on hot water

When the gas boiler starts the first time, the air is squeezed out of the system, starting from the boiler itself, which he leaves through the automatic air vent valves. Experts explain this situation features of the design of dual-circuit boilers and believe that the pressure on the fact does not ignore.

In order for the exit air to do not accumulate in radiators, the cranes of Maevsky should be installed on them. When they are unscrewed, first with hiss leaves the air, then it starts to die gram.

In the wall-mounted models of boilers on the pump, it is planned to install a screw that allows you to remove air. It is also necessary to turn away and clamp a bit, such a manipulation helps to increase the water pressure, after which the unit operates in normal mode.

Often with such a problem are the owners of warm floors, and these are many meters of pipes, where the coolant from the boiler comes. Therefore, when you first start and a couple of weeks after it is possible to hiss and the air output from the system through automatic air vents, and the pressure in the system will be lower than normal.


The most frequent reason to summon the masters due to the drop in the pressure in the boiler. flows. Well, if it is in a prominent place, you can quickly detect hot water on the puddles and eliminate. But sometimes it is very difficult to visualize, for example, inside the warm flooring system. In implicit cases, the coolant “disappears” from the contour, and the pressure in the system does not rise.

You can determine the place of breakdown, walking in a dry cloth over the entire surface of the pipes, including joints, inspect the walls on the subject of subtops. Pre-turn off the heating from the boiler and drain the coolant. You can use the compressor to pump the air and the sound of the leakage. In the most difficult cases, thermal imager will come to the rescue.

Aerial traffic jams

Possible reason why pressure drops in the gas boiler and without leaks. the formation of air traffic jams. They are formed due to:

  • Invalid filling of the heating system. a lot of air was present in the water. Specialists recommend processing the coolant with a special device before downloading in the contour, otherwise the air constipation cannot be avoided;
  • poor sealing of pipe joints and other system elements;
  • Failure of valves for air release.

Additional Information. Air traffic jams cause noises and vibrating systems, which provokes disorders of tightness of compounds leading to leaks. The coolant circulates inefficiently: gas fuel consumption will grow noticeably, while the batteries will be a little warm.

Problem with expansion tank

Usually they begin in a couple of months after the start of the heating circuit: the leaks are not observed, but the heat carrier goes, and the pressure in the mixers is reset. The problem is that the pressure in the expansion tank of the two-kilt, separated from another part of the boiler an elastic membrane, is reduced due to air bleed through the nipple on the top of the aggregate. As a result, under pressure of the coolant, the entire expansion tank is filled with water from the contour. With a further increase in pressure, there is nothing to burst, so the safety valve is triggered by the discharge valve.

note! If the problem is not eliminated, a complete rupture of the expansion tank membrane may happen, which will require its replacement.

Malfunction of measuring equipment

In cases when there are no leaks visible or determined using equipment, the system is not violated, the expansion tank is working, and the pressure in the boiler has to be constantly increased, you should call specialists and check the performance of the automation of the boiler or pressure gauge. This equipment may also fail and issue incorrect indicators. In this case, nothing else remains, except to replace the pressure gauge on the new.

Cracks on the heat exchanger in the boiler

With prolonged operation of the gas boiler, constant flushing with caustic reagents, low quality manufacturing of parts, as well as periodic emergency hydroudars, microscopic cracks appear on heat exchangers. Through them and the leakage of the coolant from the contour. When gas turns on, such cracks can lower and evaporate all moisture from the heat exchanger and combustion chamber.

Determine the localization of the problem possible by the presence of scale. Microcracks on the usual heat exchanger can be sought, and the bitters will have to replace.

Resetting of the coolant not closed tightly

One of the simplest and tribal reasons, due to which it may gradually fall the pressure on the heating circuit. a loosely screwed crane.

Other possible reasons

There are also a number of other nuances leading to insufficient pressure in the thermal system. This is:

  • heat carrier leakage at the joints of pipelines;
  • lesion of metal elements of the heating system rust;
  • Low-quality heating installation;
  • Improper functioning of automation boiler.

Why drops pressure in the repayment system

Low pressure in the boiler will suspend its functioning. If the water pressure dropped in the heating system to a minimum, the water will stop entering the boiler. If the gas pressure dropped in the boiler, the boiler will automatically turn off. In order to avoid risks related to the absence of pressure in the heating system, you should invite to the house of the engineer of their service to pass the maintenance. It will protect the operation of the boiler and will warn you, from the emergency shutdown of the boiler in winter.

How to avoid air from entering the heating system

It is very difficult to avoid hitting the air to the air system, but you can minimize the problem and learn how to easily and quickly eliminate traffic jams:

  • Need to monitor the health and tightness of all joints, shut-off reinforcement and t. D.
  • Before starting the system, in it with the help of the compressor, the air under pressure is injected by 20% large than the working. Measurement meters 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. A leakage will say the arrow of the pressure gauge, as well as a characteristic whistle. To finally make sure that the leakage place is found, it is lubricated with a thick soap solution.
  • Fill the system need cold water and smoothly. After filling, the air is released several times with air vent and cranes of Maevsky. Each time after the descent to the system fasten the water.
  • It is recommended to use stainless or bimetallic heating radiators.
  • It is also advised not to change the coolant too often. In the fresh portion of water, there are always oxygen impurities.
  • To descend the air to install air vents on all problem areas and use them regularly. Or supply radiators with automatic devices and follow their health.

The adaptation period of the system during which it is necessary to lower the air again and again and pour water. a few days.

Control devices

To control the pressure of water in the heating boiler and the heating system uses pressure gauges and thermomanometers. The latter are combined devices to control two parameters at once. After starting the circuit, you must control the indicators so that they do not go beyond the norm.

In some two-door outdoor and wall-mounted boilers, traditional shooting gauges are missing. 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 is deprived of the pressure gauge, it is provided for by a security group.

The security group itself includes the following nodes:

  • Pressure gauge or thermomanometer. to control the temperature and pressure in the heating circuit;
  • Automatic airborne air. prevents impetus to the contour;
  • Safety valve. resets the pressure of the coolant when it is excessive.
pressure, boiler, fell

Be sure to pride this node in a closed heating system.

Why drops and jumps pressure in a closed heating system?

4 factors are distinguished, more often than others causing problems when pressure drops.

A leak

Is the first thing to seek when testing a pressure gauge. Initially, inspect the joints of the pipes and valves.

And also need to walk along all heat lines and take a look at the presence of puddles, traces of water, corrosion.

  • Disable pumps.
  • Conduct pressure measurements in the system while it is in a static state.
  • If the testimony falls, it means that there is. Otherwise, the fault should be sought elsewhere.

It may not help in the plastic pipe system. To search for leakage in a similar setting, you will need to use thermal imager. And you can also test, passing the air through the strapping.

Important! Both methods imply an invitation of experienced plumbing.

  • replacement of part of the pipeline;
  • overlay a new seal;
  • Fixing weakening connections.


It is formed as a result of the loss of the coolant. It leads to:

  • drop in pressure in a closed strapping, a decrease in the speed of movement of the fluid on pipes;
  • the occurrence of noise and vibration in the system;
  • to weaken compounds;
  • corrosion pipelines.

Air falls into the strapping along with the working fluid or due to the following factors:

  • long-term simple heating in the structure;
  • incorrect installation or project calculations;
  • low pressure in pipes;
  • improper sealing of compounds;
  • current repair work.

To solve the problem, it is necessary to establish a heating feed. Such a system automatically fills the lack of fluid in the pipes. With it, it is possible to clean the strapping from gaseous substances. It is not very expensive, but requires complex installation.

To reset the air, it is also sufficient to use special cranes, which are located after a certain interval along the entire strapping. With their help, the gas bubbles are poured, if necessary. For this:

  • The problem of the problem is determined.
  • The nearest point opens a crane.
  • Under the valve is the pelvis.
  • Reset part of the coolant and air.

The wizard unscrews the crane on the radiator when the pressure in the system fell to reset part of the air and the coolant.

Aluminum radiator

The problem with pressure often appears due to the installation of such batteries. Why is this happening? Coolant, passing through the strapping, oxidizes aluminum, provoking the occurrence of rust and the release of gaseous hydrogen.

As a result, pipelines are spoiled, pressure becomes unstable and begins to decrease. Solve this malfunction can time, with the course of which the oxidation ceases. And also considers the installation of new radiators.

Damage to the gas boiler in a private house

Typically detected malfunctions in one of the three components.

Problems arise in gas boilers if they are wall and have a built-in heat exchanger.

The latter is the only component that may be damaged.

Regardless of the cause, complex repairs are required. For diagnostics it is recommended to invite a specialist.

To find a problem pump, you need to turn off them alternately from the system. Then conduct trial launches by checking the testimony of pressure gauges. Broken to the device without which when turned on, pressure drops. For repair, it is enough to replace it with a new. In some cases, it is wrapped in a fresh seal.

It is necessary to clean the contamination of suction passages. Poinons arise due to mechanical impurities in the coolant, corrosion and crystallization of salts. To prevent breakdowns periodically turn off the system for a short time. To protect against dirt, install the filter.

Expansion tanks. cylinders or membrane designs. Regardless of the type, the capacity is made of metal and equipped with a rubber part. The latter is wearing during operation, which leads to the formation of microcracks and other defects. Due to damage, the ratio of adjacent cameras changes, which leads to a failure in the system.

A similar problem is solved by the replacement of details failed. In the extreme case set a new device. The latter should be avoided because it will be necessary to remove the old device for re-edit.

An incorrect calculation of the expansion capacity also leads to a reduction in pressure. Preparing for the creation of heating, create a project.

If necessary, turn on the tank into the system, determine the required volume. Be sure to take into account the coefficient of thermal expansion. When choosing a device, focus on Plumbing and Manufacturer Tips.

pressure, boiler, fell

Attention! The insufficient volume leads to overflow, which is why the pressure rises. This may entail the formation of cracks and leaks. In such an environment, the replacement of the tank and damaged pipelines will be replaced.

How to raise the pressure in the boiler?

If the reason is the malfunction of the expansion tank, then it was incorrectly calculated by its volume or damaged by the membrane. In this case, you should either more accurately calculate the required volume, or simply replace the tank.

If the pressure has become discharged immediately after the initial start, then this is normal. In the circuit, quite recently filled with water from the water pipeline, there is a large amount of air.

Over time, it will turn into bubbles and is displayed from the pipeline, and the circuit parameters will come to normal. For faster removal of bubbles, a manual air rubber is used.

Before carrying out measures to increase pressure in the system, you must make sure of its tightness.

To do this, see the following parts of it:

  • Heating devices. often leaks appear in places of docking with pipes, possible leaks arising between separate sections;
  • Pipes. even very small cracks can often lead to leakage of the coolant;
  • Fittings are often the cause of leakage;
  • Boilers. models with two circuits have a complex internal structure: so, it should be carefully made to inspect the circulation pump, a three-way valve and heat exchanger.

Preventive measures against the appearance of air traffic jams are as follows:

  • Pay attention to the correct installation of pipes and connecting heating devices. Many problems are caused by the errors that are committed on this initial stage.
  • To prevent air traffic jams, the correct commissioning of equipment is required, before which it is important to pre-check all components and connections.
  • Before starting devices to work, check them for working. Using the compressor, you need to submit pressure, the level of which is above its normal working value.

If in 30 minutes it does not weaken, then everything is in order and the system is prepared for work. If the pressure is dramatically reduced, then leaks that should be promptly identified and eliminated before operation.

Pressure loss when cooled. What to do if it is gone

No less common problem. pressure jumps depending on the boiler operation. When it is turned off or translation to the DHW mode, the indicators may decrease to 1 or 0 atm.

In such cases, its normalization is required in the expansion tank, including the following steps:

  • Crane overlapping on the tank with the subsequent drainage of the coolant. After this stage, the pressure must completely fall.
  • Open the drain fitting and measure the pressure pressure in the tank using a pressure gauge.
  • Pump the pump to the tank air while the water will not stop dripping.
  • Pull the pre-injected air.
  • Pump the tank by air again until the pressure is equal to 80% of the working value.
  • Close the fitting and power the boiler.