No water pressure in the gas boiler

Why does the pressure drop in the boiler?

If there are faults, the entire system can suddenly fail or cease to function. Even with proper installation, this sometimes happens. Thus, a drop in values may occur, after which the room is no longer heated.

Pressure drops in the boiler can occur for the following reasons:

  • Failure of the heat exchanger. One of the most common causes of failure;
  • Leakage in the circuit. Leaks can occur due to poor pipe soldering;
  • Manufacturing defect. The presence of any defects is most often due to poor quality production;
  • Clogging. Debris in the boiler can cause a decrease in performance and even breakdown of the entire system;
  • Presence of defects. Mechanical damage to individual parts of the system can lead to malfunctions;
  • Cracks. Cracks in the boiler also cause a sharp decline in performance;
  • Wear and tear. Natural wear and tear of individual parts or the entire system can affect performance.

These faults must be diagnosed and repaired in time. Diagnose a leakage will help the part where the air enters the chamber. If, when you press on it, the liquid begins to drip, then the cause of the change in the values in the leak.

A leak is diagnosed by certain rules. First analyze the sections of the circuit that are visible, then inspect the floor or wall (in case the piping is under the floor or in the wall). Sometimes it is possible to disconnect individual sections of the circuit one by one. This way it is easier to detect leaks.

If the pressure in the boiler is constantly dropping, first of all all all fittings are checked, then the tightness is examined (usually before the heating season), all internal mechanisms are checked.

Unreliable values can also be caused by faulty instrumentation. In this case it should be replaced with a new one. This should only be done after all components have been diagnosed.

Decrease of pressure in the boiler is provoked by damage of parts in the expansion tank. If there is damage from the rubber, the liquid flows into the compartment with the air, so that the pressure in the circuit decreases.

Leakage can be at the radiator or the expansion tank. Also, the drop in values can be caused by worn seals, loose fittings, the emergence of corrosion. All this does not allow the system to function fully and leads to its failure.

The pressure in the heating system: what should be and how to increase it if it falls

After a pressure failure in the heating system comes a problem. the quality of space heating in the house is falling. You can, of course, adjust the work of heating once and for a long time, but it will not last indefinitely. 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. Here you will learn how to ensure a stable rate of movement of hot water through the pipeline to the appliances. Understand how to obtain and maintain a comfortable room temperature.

The article offered for review details the causes of pressure drops in closed and open systems. Effective methods of balancing are given. The information provided for review is supplemented by diagrams, step-by-step instructions, photos and video tutorials.

Why does the pressure drop

Before you raise the pressure in the gas boiler baksi, it is worth figuring out the triggering factors. If the required parameter changes to a smaller value, the gas appliance malfunctions. The supply of liquid to the technique stops, the work of the boiler stops, as a result, there is no heating.

Specialists call several factors that provoke a decrease in pressure:

  • Using hot water. Such a problem is common, the cause is considered a device. Masters believe that in this case the manometer does not work correctly, it shows wrong values. Provoke such a situation can also cause infiltration of air in the circuit itself, or a malfunction of the three-way valve.

Pressure drop when using hot water happens often

  • Leaks anywhere in the heating system. Tightness is affected by poorly sealed joints, long used heat exchangers, pipes or radiators.
  • The presence of air s. If the seal is cracked, air masses can enter the system and adversely affect the condition of the system. This condition may also occur if the first filling of the circuits is done incorrectly.
  • Expansion tank. Problems in this element, such as ruptures or air in the nipple, also affect the pressure.
  • Malfunctioning of measuring instruments. In some situations the problem is in the device automatics and control sensors. Such a cause is not easy to determine independently, so it is worth to contact a master.
  • Damage of the heat exchanger. Cracks that appear on the walls of the heating element during prolonged use can let moisture in. The result is a reduction in the specified parameters.
  • Liquids drain cock not closed tightly. Quite a simple reason, but it occurs quite often.


It is important to follow all rules for connecting the boiler×576.jpg

In addition, provoke a decrease in pressure in the gas product is capable of improper installation. It is important to consider that the values in the pipes are affected by their height and length, the effect of water on other parts, the arrangement of the main paths.

If the pressure began to decrease more and more often, it is required as soon as possible to find out the cause and try to solve how to raise the pressure on the boiler baksi.

Norm and control

We have already said that the pressure in the gas boiler should be within 1.5-2 atmospheres. this is the norm for the system, which is put into operation and is in the heated state. In high-rise buildings heated by centralized boilers, this indicator is higher. Here the pipes and batteries must be able to withstand not only high pressure, but also water hammer. a sudden increase in pressure.

Boiler Burner Dose Not Fire Also No Water Pressure

If for centralized systems the fluctuations are typical, then for standalone heating they are a rarity. the volume of coolant is not so large to observe serious jumps. When cold, the normal value is 1-1.2 atm., and in the heated state. a little higher.

In private households, autonomous heating systems are used with power from single-circuit and double-circuit boilers. The latter are becoming more and more common. In addition to heating, they solve the problem of hot water preparation. One circuit in them heats the coolant circulating through the pipes, and the other ensures the operation of the hot water system.

How to solve the pressure problem?

The first thing to do in such cases is to check the valve. Before starting the test, make sure that the make-up valve is closed as tightly as possible. Check what will happen when the gas boiler is off. To do this, disconnect it from the mains. The same thing happens even when it is switched off. there is only one solution. call a service technician who will replace your faucet. It is not recommended to replace the tap at home by yourself, because you may need special equipment to perform this work.

water, pressure, boiler

If the pressure will only decrease while the boiler is on, and it does not happen during the use of warm water, but only when turning on and off the boiler, then the cause of failure is most likely in the expansion tank. You can easily do it yourself at home. Enough to externally find the fault, most often a scratch or a small hole, then patch it with special glue. If the hole is big, then the repair requires the help of specialists or a complete replacement of the expansion tank.

Autonomous gas heating and running water heating. a measure that many people think about. After all this kind of fuel is considered to be one of the most economical. Sometimes the owners of such installations are faced with a situation where the pressure in the gas boiler drops, and the reasons may be different. No need to get upset and panic. First of all you need to establish the symptoms of failure. After that, the main factor that led to this situation is found out, and then eliminated.

How to raise the pressure in the boiler?

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

If the pressure began to drop immediately after the initial start, it is normal. In the circuit, very recently filled with water from the water supply, there is a large amount of air.

Over time, it will turn into bubbles and withdraw from the pipeline, and the parameters of the circuit will come back to normal. A manual air vent is used to remove air s more quickly.

Before taking measures to increase pressure in the system, it is necessary to make sure that the system is airtight.

To do this, you need to inspect the following parts:

  • Heating devices. often leaks appear in the joints with the pipes, leaks occurring between the separate sections are also possible;
  • pipes. even very small cracks can often lead to coolant leakage;
  • fittings. often the cause of leaks;
  • Boilers. Models with two circuits have a complex internal structure: thus, the circulation pump, three-way valve and heat exchanger must be carefully inspected.

Preventive measures against air s are as follows

  • Pay attention to the correct installation of pipes and connection of heating devices. Many problems are caused by mistakes made at this initial stage.
  • To prevent air s, it is necessary to properly commission the equipment, before which it is important to pre-check all components and connections.
  • Before starting the equipment, check to see if it is working properly. It is necessary to apply a pressure which is ¼ of the normal operating pressure of the compressor.
water, pressure, boiler

If it does not loosen within 30 minutes, then everything is fine and the system is ready to work. If the pressure decreases sharply, there may be leaks, which should be promptly identified and eliminated before the operation.

Causes of increased pressure in the gas boiler

Detect an increase in pressure in the gas boiler helps, in addition to indicators of the manometer, frequent water release through a safety valve and blocking the operation of the device. Having determined the high pressure, first of all, the excess air is discharged through the Maevsky cocks and disconnect the boiler. There may be several reasons for malfunction.

To increase the pressure in the gas boiler can cause damage to the secondary partition heat exchanger, which serves both to isolate and increase the area of contact between the two circuits. heating and hot water.

The secondary heat exchanger draws water from the heating circuit to prepare and supply DHW in a two-circuit boiler. Damage to the baffle causes water from the DHW circuit to squeeze into the heating system, increasing the pressure in the system.

Replacing the heat exchanger will solve the problem. Make repairs yourself can be done, but it is not advisable to do so, as interfering with the work of the gas equipment requires knowledge and experience in this area. In addition, self-repair of the boiler will deprive you of the right of warranty service.

Failure in the gas boiler automatics or loose impeller of the pump, which sucks air also increases the pressure in the gas boiler. Equipment failures that lead to violations of the normal head, can be as a consequence of a factory defect, breakage of the control board, improperly configured system. Only a qualified technician can eliminate this kind of problem.

Why the pressure increases in closed boilers

The main reasons why the pressure rises are as follows:

  • The heating circuit is filled from the upper part;
  • rapid filling of the heating medium during start-up;
  • Loose pump fan, through which the air flows;
  • breakage of the air vent;
  • The system has not been vented after repairs.
water, pressure, boiler

The heating circuit must be filled from the bottom and the safety valves must be open. Fill gradually until the liquid begins to drain from the safety cocks. Before you start filling the heating circuit, all air vent parts should be treated with a soapy solution, so you can check their normal operation.

Important! If the discharge pump is leaking air, it is the cause of the increased pressure.

How to solve the pressure problem?

The very first thing to do in such cases is to check the valve. Before starting the check, make sure that the make-up valve is closed as tightly as possible. Check what will happen when the gas boiler is off. To do this, disconnect it from the mains. If the same thing happens even when the valve is off, there is only one solution. call a service company to replace the valve. To replace the valve yourself at home is not recommended, as to perform this work may require special equipment.

If, however, the pressure will only decrease while the boiler is on, and it does not happen during the use of warm water, but only when turning on and off the boiler, then the cause of the failure is most likely in the expansion tank. To fix the problem you can easily do it yourself at home. It is enough to externally find the fault, most often it is some scratch or small hole, then patch it with a special glue. If the hole is large, then the repair will require the help of specialists or a complete replacement of the expansion tank.

For heating networks in private homes and apartments is advisable to use boilers with a closed loop coolant, ie.е. two-circuit. This design allows you to increase the pressure of the working fluid in the circuit.

High pressure in the heating system provides safety and a higher boiling point of the coolant, therefore the economic effect of the installation increases, and reducing the pressure leads to problems in the system. So let’s look at why the pressure in the heating system of a two-circuit boiler drops and how to raise it.

Control of boiler unit parameters is carried out by measuring instruments. pressure gauges, main and auxiliary. If the pressure gauge must be part of the I&C measures, choose models with electronic sensors.

Factors that affect the pressure inside the circuit:

  • The impact of the coolant on the walls of the heating network elements;
  • The height of the pipes, hanging radiators and boiler unit;
  • The design of the main sections of the pipeline.

The value of pressure for standalone heating is not regulated. Allowable values of network parameters are calculated on the basis of the data of a particular object:

  • Type of boiler, pipe characteristics (diameter, presence of reinforcement, etc.).), type and number of radiators;
  • The place of installation of the equipment, the length of the circuit;
  • Floors of the house;
  • Parameters and condition of the external water pipeline.
  • The presence of leaks in the pipeline;
  • Violation of the boiler, cracks on the surface of the heat exchanger;
  • Malfunction of membrane valve, which is responsible for the safety of boiler equipment;
  • Failure of the membrane of the expansion tank;
  • Leakage of the hot water circuit.
| Denial of responsibility | Contacts |RSS