Following the failure of the pressure in the heating system comes the problem - falling quality space heating in the house. You can of course adjust the heating work once and for a long time, but infinitely long this period will not be. Once the normal system pressure changes, wherein significantly.
We'll tell you how to control physical parameters of coolant. You will learn how to provide a stable speed of the heated water through the pipeline to the devices. You understand how to make and maintain a comfortable indoor temperature.
In consideration of the proposed article detailed causes a pressure drop in the closed and open systems. Given the effective balancing methods. Presented for the inspection information supplemented schemes, step by step instructions, photos, and video tutorials.
The content of the article:
- Types pressure in heating
- The consequences of instability in the circuits
The pressure heating system in an open
- Balancing the dual-circuit open heating systems
- Circulation pump for open heating systems
The pressure in the closed heating system
- coolant leak search steps
- Pressure drops in the boiler
- Low pressure due to the expansion tank
- Conclusions and useful videos on the topic
Types pressure in heating
Depending on the current movement of the principle of coolant in the heat conductor circuit in the heating main role is performed by a static or dynamic pressure.
Static pressure, also known as gravitational, develops due to the force of gravity of our planet. The higher the water rises along the contour, the greater its weight presses on the pipe walls.
When lifting the coolant at a height of 10 meters static pressure is 1 bar (0.981 atmosphere). It calculated on the static pressure open heating system, its maximum value - of the order of 1.52 bar (1.5 atmosphere).
The water in the heating circuit gravity moves due to the density difference of the heated and cooled water. When installing the boiler below the heating circulation pressure increasing device
heating circuit with the natural movement of the coolant pressure is small. Its excess with the surplus coolant is discharged through the open surface of the surge tank
Pressure gravitational system should be enough for a heat transfer medium through the pipeline, overcoming corners and vertical sections. In order to reduce pipe resistance, increase the diameter of pipe
problems of insufficient pressure to move the coolant solved by setting circulators
Using a pump can be used in the construction of the pipe system of smaller diameters, as flow resistance is overcome by using the installed unit
Forced-type heating system is now arranged by closed expansion tank equipped providing space heat carrier during its expansion upon heating
Expansion tank in the heating circuit pump is regarded as a reference point, wherein the pressure changes developed by the pump to the suction inflator value
The pump with a closed heating system tank compulsorily include a pressure relief valve, the normalizing value by the reset drains surplus coolant in
gravity type heating apparatus
Open the expansion tank
Using pump tsirkulyatsionnnogo
Reducing Diameter of Pipe
Sealed expansion tank
Expansion tank as a reference point
Devices for control and adjustment
The dynamic pressure in the heating circuit is developed by artificial means - using an electric pump. Typically, the dynamic pressure calculated closed heating systems, which contour is formed by tubes considerably smaller diameter than the open heating systems.
Average value of the dynamic pressure in the closed heating system - 2.4 bar or 2.36 atmosphere.
The consequences of instability in the circuits
Insufficient or higher pressures in the thermal circuit equally poorly. In the first case, part of the radiators will not effectively heat the premises, the second - break the integrity of the heating system, will break down some of its elements.
Proper piping will connect the boiler to the heating circuit as necessary for quality work teplosistemy
The growth of the dynamic pressure in the heating conduit occurs when:
- coolant too overheated;
- Pipe section insufficient;
- boiler and the piping were overgrown scum;
- air locks in the system;
- set too powerful booster pump;
- It occurs makeup water.
Also, increased pressure in the closed circuit causes incorrect balancing valves (the system is regulated) or failure of individual regulators, valves.
In order to control the operating parameters in closed heating circuits and a group of security set for their automatic adjustment:
For the formation of the heating system is required for normal operation of the pressure safety band is used
The group used to automatically adjust and control the pressure in the system, there is a pressure gauge, piston air vent and safety valve
security group is set on the boiler feed systems dvhtrubnyh pipe and the main pipe portion of the supply pipe systems
The functional components of a security group to provide output air atmosphere threatening form plugs, and the excess pressure and coolant, increasing in volume at boiling
security group in the system is required to include a closed expansion vessel, not having a natural potential for pressure reduction as open circuits
In embodiments, heating of commutator requiring the use of circulating pumps, the security group to complete the duplicate deaerators Manifold
Refuse security group setup is acceptable if the coolant is heated by the boiler, equipped with its own set of similar means in miniature. EXAMPLE: Gas wall boilers, part of the floor and the pellet
security group components may be located in different parts of the system, but it is important to observe one condition - the safety valve should be above the boiler
The standard version of the security group
The band for monitoring the pressure
Place setting security group
Sbors surplus air and water
Security group of closed systems
Safety features in the radial layout
Prerequisites for the rejection of the security group
Separate installation of safety equipment
The pressure in the heating pipe falls for the following reasons:
- leakage of coolant;
- pump malfunction;
- breakthrough membrane ekspanzomata, cracks in the walls of the usual expansion tank;
- failure security unit;
- drain water from the heating system of the feed path.
The dynamic pressure is increased, if the clogged pipes and radiators of the cavity if contaminated filters traps. In such situations, the pump operates with high load, and the efficiency of the heating circuit is reduced. A standard result overpressure leakage values are in the compounds and even rupture of pipes.
Pressure will be lower than it is necessary for the normal functional, if insufficient power trunk mounted pump. He will not be able to move the coolant to the required speed, it means that the device will be available a few ostyvshaya working environment.
The second striking example of pressure drop - duct closed valve. A sign of these problems is the pressure loss in a separate segment of the pipeline downstream of the obstacles to the coolant.
As in all heat circuits are devices that protect against excessive pressure (at least, safety valve), Low pressure problem occurs much more frequently. Consider causes drop and methods to increase the pressure and hence improve the circulation of water in heating systems open and closed type.
The pressure heating system in an open
In contrast to the closed-loop heat properly building an open heating system does not require balancing the years of operation - it is self-regulating. The boiler and provide a constant static pressure water circulation system.
The density of the heated water, following on the feed riser, lower than the density of the cooled heat carrier. Hot water tends to take the highest possible point of the contour and the cooling - to be at the very bottom.
The time required for the water circulation pressure is reached the pressure in the feed booster pump or standpipe (+)
Pressure developed by a column of water in the feed riser, promotes circulation of the coolant and compensates for the resistance, existing in the conduit circuit. It is caused by the friction of the water against the inner surface of the tube, and local resistance (turns and branch pipe, the boiler fittings).
Incidentally, an increased-diameter pipes are used for the assembly open heating system namely to reduce friction.
To understand how to increase the pressure in an open heating system, one must first understand how to achieve a circulation pressure in the thermal circuit.
Its formula is:
Ru = H • (pabout-Rg),
- Ru - pressure circulation;
- h - vertical distance between the centers of the boiler and the lower heating radiator;
- Rg - the density of the heated coolant;
- Rabout - the density of the cooled coolant.
The static pressure will be higher if the distance between the central axes of the boiler and nearest thereto batteries will be as large as possible. Accordingly, circulation of the coolant intensity is higher.
To achieve the maximum possible pressure in the heating circuit, the boiler must be lowered as low as possible - in the cellar.
The closer to the radiator feed circuit to the boiler, the better it gets warm. Regulators allow the heat to distribute between all the radiators of the heating system
The second reason for the pressure drop in the open heating system is related to its self-regulation. By heating the coolant temperature changes varies the intensity of its flow. Increasing water heating circuit heat in cold winter days, home drastically reduce its density.
However, when passing through the radiators, the water gives up heat to ambient atmosphere, thus increasing its density. A formula provided above, the high density difference between the hot and chilled water circulation contributes to build pressure.
The stronger the heated-up coolant and the colder areas of the house, the higher will be the pressure in the system. However, after the atmosphere of the room warms up and heat radiators will decrease the pressure in an open system will fall - to reduce the difference between the temperature of the water in the supply and return pipe.
Balancing the dual-circuit open heating systems
Gravitational heating systems made with one or multiple loops. Thus the length of each horizontal looped pipeline should not exceed 30 m.
But in order to achieve optimum pressure and the pressure in the open system with natural movement coolant piping to perform better even shorter -. less than 25 m then the water will be easier to deal with hydraulic resistance. In circuit with several rings, in addition to length restrictions must be observed condition for radiators - the number of sections in all rings should be approximately equal.
Lack of pressure in an open system, dual-circuit heat occurs due to designing errors or contamination of the pipeline (+)
Horizontal balancing rings being part of the vertical contour is required at the design stage of the heating system. If the flow resistance of a ring will be higher than the rest - the static pressure in it will not be enough and the pressure almost ceases.
To maintain the necessary pressure in the dual-circuit heating system, it is required to reduce the cross section of pipe on the approach to the radiators. You can also set in front of radiator valves operate thermoregulation (manual or automatic).
Balance the dual-circuit open system, you can:
- Manually. Start heating the system, we measure the temperature of the atmosphere after each heated space. Where it is higher - fasten the valve, where lower - untwist. To adjust the heat balance of the need to perform temperature measurements and adjustment of valves several times;
- Using thermostatic valves. Balancing takes place almost on their own, you need only set the desired temperature in each room Hand valves. Each such unit will control the supply of coolant to the radiator itself, increasing or reducing the supply of coolant.
It is particularly important that the amount of the total hydraulic resistance of the heating system (all rings composed contours) was not higher than the circulating pressure. Otherwise warm coolant and attempts to balance the system will not improve the circulation.
Circulation pump for open heating systems
It happens that the balancing effect of gravitational heating circuit system measures fail. Not all reasons for the low pressure are solved settings - pipes incorrect diameter not corrected without full reconstruction of the contour.
Then, to increase the pressure and improve the movement of water without significant alteration of the heating, the system the circulation pump mounted or booster pump device. The only thing that it requires installation - the transfer of the expansion tank and its replacement by the membrane ekspanzomat (closed tank).
In a serious pressure drop is needed circulation, and more powerful booster pump. However, booster pumps are not suitable for open heating systems, as develop significant dynamic pressure
The power consumption of the circulation pump does not exceed 100 watts. Therefore, the fear that he will push the heat transfer fluid of the circuit, it is not necessary.
The volume of water in the heating system is more or less constant, provided for filling the open control loop. Therefore, no matter how much water the circulation pump is not pushed in front of the contour, the same goes with it in the return pipe.
Adjusting the pressure in the system to the required heat, the pump will allow it to lengthen, shorten the diameter of the pipeline and achieve a balance circuit at high flow resistance.
The pressure in the closed heating system
Installation of modern boilers, particularly a bypass, called the sellers the perfect solution for home heating. In a qualitative installation of a new boiler Forced closed system regularly serves for several years, but once the pressure therein is reduced abruptly or gradually. How to find the cause of the low dynamic pressure?
Closed heating system needs immediate attention. Drop or pressure rise equally dangerous for her. Left without heating in winter - a homeowner's worst nightmare.
When heated coolant expands. for expansion space provides one of the chambers of the expansion tank. If it is filled to the limit, excess coolant is discharged through the safety valve
Safety valves for large-scale heating networks are available with flange for connection to the pipeline for domestic - threaded
Most often, the safety valve of small private networks installed in the security group on a common manifold for the three instruments
If the design of the system determines the installation deaerator for risers or radiators, the contour after the boiler is mounted with a manometer valve
When the pressure above the allowable limit in the device the spring is compressed with the piston, opening a channel for emptying
Setting the safety valve is made so that the upper limit does not exceed the maximum allowable for the weakest component of the system. The lower limit is selected, based on the minimum values for normal operation
If there is a risk of pressure drops below normal operating values set makeup valve. He will join the reserve of coolant in case of an active exhaust air volume of its greatly reduced
Inside the device is installed membrane. If the pressure membrane tension weakens, it allows pried a spring access opening of the water supply system
An apparatus for reducing the pressure
Safety device on a flange
Installation of devices on a common collector
Safety valve with pressure gauge
The principle of operation of the safety valve
Rules setting of the safety valve
Drains with manometer valve for heating systems
Specificity of the heating circuits feeding valve
First of all, it is checked and the step-up, and circulation pump, Available in a thermal circuit. This device wears faster than the boiler ekspanzomat or conduit, so its state is determined first. It is important to make sure that a "silent" pump supplied power supply and only after taking steps to replace the device.
In general, rational embed the heating circuit pump, two pre - one in the main pipe, the second bypass. Closed heating system can not operate at low dynamic pressure. Therefore, the spare pump is included in time, will protect the house and the pipe from freezing.
If the pump is not defective, the source is the pressure loss in the boiler or in the piping system. Boiler check the latest first - heating circuit.
coolant leak search steps
Independently detect leakage in the heating system is possible if the tubes are open, there is access to cranes and all the connecting elements. It is also necessary to remove a decorative trim radiators.
You need to go around the heat loop with a flashlight, carefully studying each joint, each element of the system (boiler connection too). We are looking for water puddles, wet spots on the floor, traces of dried water, stains on rusty pipes, batteries and shut-off valves.
Take a small mirror, is illuminated flashlight and inspect the back side of each section heating radiator. If the battery prefabricated, cast iron or aluminum - should inspect the connection between the sections. Corrosion, rust stains - a sign of leakage, even if the floor is dry under the radiator.
There are situations when the pressure in the circuit falls slowly, day by day. Moreover, distinct traces of a leak in the heating system or floor absolutely no elements. Rather, there is a leak and a lot of them, but to find them is impossible.
Leaking water evaporates in the pipe, a radiator or a floor surface, i.e. appreciable puddle is formed. It is necessary to identify the places of possible leakage of coolant, put under these soft sheets - suitable tissue or toilet paper. Several hours later, check the paper for moisture. If wet - hence leakage here.
Serviceability of boiler safety group is not only the pressure gauge and air vent valve predokhranitelnogo. Neither her element or plug connections should not leak
The house is equipped with a heating system, partially hidden pipe leaking find yourself impossible. We can only cause heating engineers who perform searches leaks thermal circuit with the help of special equipment.
Thermal Leak in the heating system is performed in a certain sequence. First of drained coolant circuit.
Then to the whole heating pipe or to its segments, equipped with shut-off valves, connected via a threaded connection compressor. In an extreme embodiment, the conduit can be connected to the pump motor.
A few minutes from the beginning of the air injection in the thermal circuit in the ground leakage hear a distinguishable sound of air escaping. Each embedded in a wall or a floor heating system with a portion detected by the sound leakage must be opened from the screed.
Further leakage is eliminated replacement pipe segment constriction connection reeling fum tow or tape, removal and installation of the new valves.
Pressure drops in the boiler
We note immediately that determine the exact damage to the boiler equipment is only capable Heating engineer service. Those. independently and find out, especially to eliminate the serious damage caused by the pressure drop in the boiler, the landlord can not.
Consider the possible causes of "creeping" the pressure change in the boiler manometer occurring at an external boiler serviceability.
A crack in the heat exchanger. Over the years of operation the heat exchanger in the boiler wall can receive microcracks. Reasons for their formation - the wear assembly, weakening strength washes, crimping (water hammer) or workmanship. Heat transfer fluid flows through them and boiler makeup water is required every 3-5 days.
Visually not detect leakage - water flows slightly when the burner is accumulated in the boiler is vaporized moisture. Require replacement of the heat exchanger, at least get it to solder.
Three-way valve is ideal for mnogokoltsovyh heating systems. However, the capacity of the crane is firmly linked to how frequently it will be cleaned of contamination
Pressure is growing due to an open feeding tap. Against the background of low dynamic pressure in the boiler and a high pressure in the water, through the make-up valve in the heating system flows "extra" water. The pressure in the thermal circuit increases until it is reset by requiring relief valve of the boiler unit.
If the pressure in the water subsides, the coolant heating circuit transmitting its admission to the boiler, whereas the heating system pressure drop. A similar problem occurs with faulty make-up crane. It requires either close the valve or replace it.
pressure increase due to the three-way valve. When the valve failure, mounted on a two-circuit boiler, the water from the "economic" heating sector will be supplied to the heating system. Three-way valves require cleaning or replacement.
Indications of the boiler pressure gauge does not change. If the changes of working conditions of the boiler, increasing or decreasing temperature in the loop gauge shows the same pressure - it is "floating". Those. through manifold him nabilas dirt from the heating system. Replacement pressure gauge is required.
Low pressure due to the expansion tank
FROM double-circuit boilers in closed heating systems often occurs such a situation: when starting the heating mode increases sharply of Boiler pressure gauge. If the entire circuit is filled with water - the pressure builds up to 3 bar, and a relief valve is activated, resetting of the water.
The homeowner will switch off, waiting for the cooling water. When the pressure drops to a minimum. Next host then tries to switch on the boiler. But the machine does not work, it gives a signal "accident". Although sometimes unable to activate a bypass operation of the boiler, if the pressure drops too much.
Ekspanzomata position near the boiler due to its importance for the thermal system. The condition and serviceability of the expansion tank is necessary to closely monitor
We can only try to raise the pressure, topping up the water in the system in a "cold" mode (the burner) and achieving a pressure gauge readings at 1.2-1.5 bar. But the boiler restart occurs with the same result: the pressure increases; activated relief valve; water is discharged; at a minimum pressure; the boiler does not want to work.
The reasons for this failure may be several. However, a frequent source of problems - expansion tank. It does not matter where it is located - inside or outside the boiler.
Ekspanzomat divided by a flexible membrane into two parts. In a heat transfer fluid in another gas (typically - nitrogen) under a pressure of 1.5 bar. Expanding upon heating the water contained in the thermal circuit, presses the membrane into the gas compartment membrane tank. To compensate for the increased pressure in the system, gas in the compressed ekspanzomate.
After years of use closed heating circuit nipple, through which the gas injection performed in the expansion tank begins to leak. It happens that the gas throw yourself homeowners do not understand the purpose of the pin.
In either embodiment, the gas in the event ekspanzomate becomes smaller and smaller. Shortly expansion tank is no longer able to compensate for the expanding coolant pressure in the system reaches its maximum value.
A faulty expansion tank closed heating system responds rapidly rising and falling of the dynamic pressure
We look at how to solve the problem of shortage of gas in ekspanzomate. First turn off the boiler if it is electric - from the power supply too.
If the expansion tank is integrated in the boiler, it is necessary to block the access of water into both of its contour (or one). Drain the water from the boiler completely. If ekspanzomat is separate from the boiler, you need to "his" fragment of the total pipeline network, and drain the water out.
After taking the car pump equipped with a pressure gauge (manometer need necessarily) attached to the nipple on ekspanzomate and inflate it. From the locked pipe sector (or the boiler, if the tank in it) will water - swing on.
Watching the pressure gauge pump. Water ceased to flow, and the pressure has reached 1.2-1.5 bar - stop pumping air.
It remains open shut-off valves, energize the circuit with water to 1.2-1.5 bar, then turn on the boiler. The heating system will work. Having discovered that the problem with the pressure re-emerged after a while - replace the nipple ekspanzomata, it is very flowing.
Note that a tank can be another problem, more complex - membrane rupture. Then pumping the air does not help, it is necessary to change ekspanzomat.
Conclusions and useful videos on the topic
Clip # 1. How to implement balancing radiators in domestic heating system. Recall that no valves on each heating radiators do not get a balanced system.
Clip # 2. Firing recommendations to restore the operating pressure in the heating circuits closed. The video also explains how the pump ekspanzomata, lost the "factory" gas:
Properly balanced heating system will serve several years. But once the change of coolant specifications or will fail the responsible elements of the thermal circuit. Therefore, monitoring of the performance of the coolant gauges need to keep constantly in order to respond in a timely manner to the pressure drops.
Please write a comment if you have any questions on the subject of the article. We are looking forward to your stories about his experience in the normalization of the pressure in the heating circuit. We visitors are prepared to discuss points of contention in the text box located below the article section.