Piping schemes in heating systems
Single-pipe systems have three significant disadvantages:
Two-pipe systems
. Two pipelines, direct and return, are connected to the heaters with the help of bends. Water enters each radiator at the same temperature, which allows you to use
radiators are the same size. The diameters of the supply and return pipes, as well as the dimensions of the fittings (connections) are smaller than in single-pipe systems. It is possible to carry out hidden laying of pipelines in a concrete floor screed or under plaster or in a plinth box. These systems make it possible to regulate the heat transfer in the room, for which a thermostatic valve is installed on each radiator, with the help of which the regulation process is carried out automatically. Another advantage of two-pipe schemes is that sections of the heating system here can be put into operation in stages, as the floors are built. Vertical two-pipe systems can also be used in houses with a variable level of floors (that is, when the floors are lined up vertically in a checkerboard pattern).
Technology for pressure testing of the heating system
In the process of filling the system, the liquid is supplied under moderate pressure, which makes it possible for it to gradually fill all the elements of the system. Air must be bled from the system from time to time.
In apartments of multi-storey buildings, leaks are detected by testing with a pressure of 20 - 30% higher than the working one. For this, a special press is used to pressure test the heating system, and the pressure is controlled by a pressure gauge. After reaching the required pressure, the system is left for 30 minutes. If the pressure subsequently decreases, then there are leaks or leaks in the system.
The most common cause of loss of tightness is damage to gaskets, valves, junctions or pipe bends, wear of threaded connections or heating radiators. After troubleshooting and re-checking, a act of testing the heating system
. A heating system that is ready for start-up without damage and leakage of the coolant is considered to be pressurized.
Crimping of a warm floor, features of carrying out
In addition to the heating system, the underfloor heating also needs to be checked regularly. Pressure testing of the warm floor is carried out until the pressure in the system stops dropping. The required pressure in the system is achieved by using a pressure test pump. In apartments of multi-storey buildings, medical and educational institutions, pressure testing is carried out by special supervisory authorities. After the tests, a hydraulic test report is drawn up, which indicates the control parameters and the date of the test.
During the installation of the underfloor heating system, different links may become clogged with small debris, and the connections may be deprived of tightness. All this can interfere with the normal functioning of the warm floor, cause leaks or loss of efficiency. Crimping of the warm floor is carried out immediately after installation before pouring the screed or laying the finished floor.
During pressure testing, the underfloor heating system is filled with water from the central pipeline through the valve for filling and draining the coolant. The test pressure during a hydraulic test should be 2.5 - 2.8 atm. After filling the system, it must be left for 20 - 30 minutes, leaks should be identified and eliminated.
When pouring water into the underfloor heating system is difficult, pressure testing can be done by forcing air masses.To do this, you can use a compressor or a car pump with a pressure gauge, which must be connected to any valve in the system. Also, for crimping underfloor heating, you can use special crimping machines, the cost of which is usually quite high. The pressure during pressure testing with air should be 2 - 3 times higher than the working one. For example, at an operating pressure of 1.5 - 2 atm. It is necessary to achieve a pressure of about 5 atm.
After filling the system with water or air, check all connections for leaks. The filled underfloor heating system can be left under pressure for 24 hours to check the strength of the connections and detect leaks. It should be remembered that with temperature changes in the room, the pressure in the system also slightly decreases. After pressing the underfloor heating, you can lay the finishing floor or pour the screed.
The overall reliability of the heating system depends on the efficient operation of each node. The physical condition of all elements individually and as a whole must be subjected to periodic testing. The results obtained after hydraulic testing of pipelines of heating systems must comply with building and installation standards.
One of these methods is crimping. For legal entities or individuals, the company conducting this procedure may issue a confirming act.
Requirements for heating systems
Heating in apartment buildings is based on the result of many engineering calculations, which are not always very successful. The process is complicated by the fact that it does not consist in delivering hot water to a specific property, but in evenly distributing water to all available apartments, taking into account all the norms and necessary indicators, including optimal humidity. The effectiveness of such a system depends on how coordinated the actions of its elements, which also include batteries and pipes in each room. Therefore, it is impossible to replace radiator batteries without taking into account the characteristics of heating systems - this leads to negative consequences with a shortage of heat or, conversely, its excess.
As for the optimization of heating in apartments, the following provisions apply here:
- Safety requirements are determined by the temperature of the heat carriers - the temperature in the battery should not be more than twenty degrees at which the materials can ignite (limits from sixty-five degrees to one hundred and fifteen, depending on the season);
- Water temperature up to one hundred and five degrees Celsius is the basis for taking measures against boiling liquids;
- The normative limits for the temperature of the water that flows through the heating batteries is seventy-five degrees, if the indicator is exceeded, the batteries must have restrictive structures;
- In mid-latitudes, the heating season starts from mid-October to mid-April.
In any case, if something bothers the owner, it is worth applying to the management company, housing and communal services, the organization responsible for the supply of heat - depending on what exactly differs from the accepted norms and does not satisfy the applicant.
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Heating the apartment is the concern of either an authorized organization or the owner of the apartment. In the second case, everything is very clear - the system of individual heating of the dwelling provides the ability to maintain any necessary temperature regime in each room. The first option is much more difficult.
Heating standards are developed based on sanitary standards for both residential and non-residential premises. The basis, in the latter case, is the calculation of the needs of an ordinary organism.
The calculation process itself is quite complex. These values are called optimal. They are legally established and displayed in SNiP.
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Correct crimping technology
The liquid, which enters under slight pressure, displaces up the air that has accumulated inside. Then she fills in all the elements. Several times you will need to bleed it from time to time.
In a multi-storey building, in order to detect the presence of leaks, a test is carried out by increasing the working pressure by about 20-30%. A press for pressure testing of heating systems is usually used for these purposes. The setpoint must be monitored with a pressure gauge. It must also be ensured that the set value is maintained for at least 30 minutes.
Thus, immediately in hot pursuit, you can find places where problems are observed. Such places can be heating radiators, various gaskets, a section of pipes for heating, valves or threaded connections.
Systems such as systems embedded in the floor require special attention. Repair work can be carried out immediately after partial or complete draining of water from the system
The crimping procedure must be repeated until the pressure gauge shows that the arrow has stopped falling. To create the desired level, regardless of the type of coolant, you will need a pump for pressure testing heating systems.
In multi-storey buildings, in administrative buildings, in children's or medical institutions, the acceptance of systems must be carried out without fail by special supervisory authorities. In the act conclusion, which will be compiled by a specialist, both the time when the test was carried out and all control parameters will be indicated.
During the installation work in various parts of the heating system, it will not be possible to avoid clogging of the equipment through small debris, sludge, dust, as well as residues of materials that were used in the assembly of the system. All this dirt can interfere with the normal functioning of the heating system.
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You have probably heard that before starting a water heating system, after its installation or repair, it is necessary to pressure test it. Therefore, many are interested in when pressure testing of the heating system must be carried out, what it is, by whom and how it is carried out, depending on the type and number of storeys of the house. In this article, we will try to answer these questions.
Pressure testing of a heating system is a hydraulic (or pneumatic) test of its elements to determine their tightness and ability to withstand the design working pressure of the coolant during operation, including water hammer. This is necessary in order to identify possible leaks, its strength, quality of installation and ensure reliable operation of the system throughout the entire heating season.
When should it be done?
Pressure testing or hydraulic (using water), and sometimes pneumatic (using compressed air) testing of heating systems is carried out in the following cases:
- In new, just mounted - after the completion of installation work and putting it into operation;
- Those that have already been used:
- after the completion of the repair or replacement of any of its elements;
- in preparation for each heating season;
- in apartment buildings also at the end of the heating season.
Who Should Carry Out the Examination
In multi-apartment residential buildings, industrial or administrative buildings, pressure testing of heating systems should be carried out by certified specialists of the services entrusted with their operation and maintenance. In private houses, with autonomous heating, this work can be done either by specialists or independently (most often, in cases where the heating system in the house was installed by oneself). In any case, the requirements (by method, maximum pressure, time) and the regulatory rules for conducting such tests, which are regulated in SNiP for this type of work, must be observed.
The temperature of the heating batteries in the apartment standards
The norms for heating apartments determine the specific value of a sufficient indicator for residential and non-residential premises, with permissible deviations from their indicators.
They are developed easier than for work premises, since those living in housing show low and, at the same time, stable activity:
- For residential premises, the air temperature is from 20 to 22 degrees Celsius, while the permissible limits are from 18 to 24 degrees;
- If we take corner rooms, then here the indicator should not be less than a twenty-degree mark, since such rooms are more susceptible to the action of low external temperatures and winds;
What temperature should be in the apartment during the heating season?
What to do if the batteries in the apartment are cold, read here.
- The kitchen is a working room, where, in most cases, its own heat source is located - an electric or gas stove. The temperature in this room should be between 19-21 degrees. Permissible is from 18 to 26 degrees;
- The optimum temperature for toilets is 19-21 degrees. Limits range from 18 to 26. Anyway, bathrooms are not among the coolest rooms;
- The bathroom is a hot room because it has a fairly high level of humidity. The minimum temperature indicator here leaves from 18 to 24 degrees. Permissible maximum - 26 degrees. But, nevertheless, even at 20 degrees, the comfort of using this room decreases;
- For non-residential premises, the temperature calculation is based on the frequency of their operation. In the corridors, 18-20 degrees is recognized as an acceptable temperature level, however, 16 is also acceptable. For storerooms, the air temperature should be 16-18 degrees. Permissible limits are 12 and 22 degrees.
Since the need for heat during sleep is somewhat reduced, according to GOST, it is allowed to lower the temperature level in residential premises to 3 degrees from 00.00 to 05.00 in the morning. Such a decrease in the norm will not be regarded as a violation.
What are the requirements for a heating system?
The heating process in a multi-storey building is based on the results of many engineering calculations, sometimes they are not so successful.
The complexity of the process is not in the delivery of heated water to the object (building), but in its uniform distribution over all apartments, on the condition that the apartments provide standard temperature indicators and optimal humidity.
How effective such a system will be directly depends on the coherence of the actions of all its elements, including pipes and batteries in each of the apartments.
For this reason, the replacement of radiator batteries, not taking into account the peculiarities of the heating system, can lead to extremely undesirable consequences: one of the apartments may experience a shortage of heat, while the other will have an excess of it.
It is through the establishment of norms that the optimization of the heating of city apartments is achieved:
- Safety requirements determine that the temperature of the heat carrier in the heating system should be 20 degrees less than the temperature of materials that tend to ignite spontaneously. For buildings of multi-apartment residential type, the normative indicator of the coolant should be in the range from 65 to 115 degrees, taking into account the season;
- When the water overheats to 105 degrees, measures must be taken against boiling the liquid;
- The normative limit for the temperature of water flowing through heating batteries is 75 degrees.If this indicator is exceeded, the battery must have a restrictive design;
- The mid-latitude heating season begins in mid-October and ends in mid-April. In reality, service providers must initiate the start of heating from the moment when the average daily temperature is not higher than 8 degrees for five consecutive days.
What to do if the pressure drops in the heating system
Expansion tank pressure.
During the operation of autonomous heating systems, the most frequent are such emergency situations in which the pressure gradually or sharply decreases. They can be caused by two reasons:
- depressurization of system elements or their connections;
- boiler malfunction.
In the first case, the leak should be located and its tightness restored. You can do this in two ways:
- Visual inspection. This method is used in cases where the heating circuit is laid in an open way (not to be confused with an open type system), that is, all its pipelines, fittings and devices are in sight. First of all, they carefully examine the floor under pipes and radiators, trying to detect puddles of water or traces of them. In addition, the place of leakage can be fixed by traces of corrosion: characteristic rusty streaks form on radiators or at the joints of system elements in case of leakage.
- With the help of special equipment. If a visual inspection of the radiators did not give anything, and the pipes were laid in a hidden way and cannot be inspected, you should seek the help of specialists. They have special equipment that will help detect the leak and fix it if the owner of the house does not have the opportunity to do it himself. Localization of the depressurization point is quite simple: water is drained from the heating circuit (for such cases, a drain valve is cut into the lower point of the circuit at the installation stage), then air is pumped into it using a compressor. The location of the leak is determined by the characteristic sound that the leaking air makes. Before starting the compressor, use shut-off valves to isolate the boiler and radiators.
If the problem area is one of the joints, it is additionally sealed with tow or FUM tape, and then tightened. The broken pipeline is cut out and a new one is welded in its place. Units that cannot be repaired are simply replaced.
If the tightness of pipelines and other elements is beyond doubt, and the pressure in the closed heating system still drops, you should look for the causes of this phenomenon in the boiler. It is not necessary to carry out diagnostics on your own; this is a job for a specialist with the appropriate education. Most often, the following defects are found in the boiler:
The device of the heating system with a manometer.
- the appearance of microcracks in the heat exchanger due to water hammer;
- manufacturing defects;
- failure of the feed valve.
A very common reason why the pressure in the system drops is the wrong selection of the capacity of the expansion tank.
Although the previous section said that this could cause pressure to rise, there is no contradiction here. When the pressure in the heating system rises, the safety valve is activated. In this case, the coolant is discharged and its volume in the circuit decreases. As a result, over time, the pressure will decrease.
Pressure control
To visually control the pressure in the heating network, dial gauges with a Bredan tube are most often used. Unlike digital instruments, these pressure gauges do not require an electrical connection. Electrocontact sensors are used in automated systems. A three-way valve must be installed on the outlet to the control and measuring device.It allows you to isolate the pressure gauge from the network during maintenance or repair, and is also used to remove an air lock or reset the device to zero.
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Instructions and rules governing the operation of heating systems, both autonomous and centralized, recommend installing pressure gauges at such points:
- In front of the boiler plant (or boiler) and at its outlet. At this point, the pressure in the boiler is determined.
- before and after the circulation pump.
- At the entrance of the heating main to a building or structure.
- before and after the pressure regulator.
- At the inlet and outlet of the coarse filter (sump) to control the level of its contamination.
All measuring instruments must be regularly verified to confirm the accuracy of their measurements.
The apartment is cold where to complain
Before going in search of heat, it should be remembered that the heat in the room will be supplied through the heating system only when the street temperature reaches a certain level.
Regulations require starting heating when the outside temperature is set to no more than 8 degrees. This temperature indicator must last five days in a row, and only after that the premises will begin to be heated.
When the heating in the house is established, and temperature deviations are observed only in your room, it is necessary to check the in-house heating system for airing.
It is enough to feel the individual batteries in the apartment from top to bottom, and vice versa. If part of the batteries is noticeably warm and the rest is cold, you can be sure that air is the cause of the thermal imbalance. Air is released using a separate valve, which is located on each radiator battery.
Before opening the tap, you should substitute some container under it. When you open the faucet, the water should come out with a characteristic hissing sound. If the water began to flow evenly and without hissing, then the air is released from the system, and the job is done.
After that, lock the valve in the closed position. After a while, check the cold places on the battery, they should warm up.
If the matter is not in the batteries and they are completely cold, you should contact the Criminal Code. The technician will come during the day. He will be able to draw up a conclusion on the temperature regime in the housing and call, if necessary, a team that will fix all the problems.
When the Criminal Code did not respond to the appeal you submitted or the appearance of the technician did not change the situation, you should take temperature measurements in the housing yourself by calling your neighbors.
When you have an instrument such as a pyrometer at your disposal, you should use it to take the necessary temperature measurements. Record all the data with an act on measuring the air temperature in the housing. It is compiled in the usual form. Let the neighbors sign the act.
You should pay attention to the fact that the temperature regime is determined by the "Sanitary and epidemiological requirements for residential buildings and premises" SanPiN 2.1.2.1002-00. Recorded measurements should be compared with the limit values specified in SanPiN
Then you need to re-go to the Criminal Code and the organization that supplies the house with heat to write a written claim
Recorded measurements should be compared with the limit values specified in SanPiN. Then you need to re-go to the Criminal Code and the organization that supplies the house with heat to write a written claim.
The document is drawn up in two copies. One of the copies should be in your hands with a stamp, signed with the data of the person who accepted the document and the date of receipt of the document. The second one must be submitted for consideration.
If you were not satisfied with the answer, then you do not need to leave everything halfway, proceed further.You should contact the district Prosecutor's Office and the Housing Inspectorate, since it is she who is authorized to monitor the work of the Criminal Code and other communal structures.
Also write a letter to Rospotrebnadzor (based on the violation of your consumer rights). You can use the Rospotrebnadzor hotline (8-80-010-000-04).
If you would like to know, or call us on:
+7 (499) 703-47-59 Moscow, Moscow region
+7 (812) 309-16-93 St. Petersburg, Leningrad region
8 (800) 511-69-42 Federal number (the call is free for all regions of Russia)!
