Scheme of the hot water system. Heat exchangers in hot water supply

Our today's topic- hot water system apartment building: diagrams, basic elements and typical problems that a homeowner may face. So let's get started.

DHW and heat supply scheme

Hot water supply scheme in apartment building can be implemented in two fundamentally different ways:

1. It uses water from the cold water supply and heats it with heat from offline source. It can be a boiler installed in the apartment, geyser or a heat exchanger using a heat carrier from a local boiler house or CHP for heating;

Please note: the advantage of such a scheme is more high quality water. It must comply with the requirements of GOST R 51232-98 (" Drinking water"). In addition, the parameters of hot water supply (temperature and pressure) rarely deviate from the nominal values; in particular, the DHW pressure is always cold water pressure taking into account the pressure loss during water intake.

1. It supplies the consumer with water directly from the heating main. This is exactly what is implemented in the vast majority of residential and administrative buildings Soviet-built, constituting 90% of the housing stock in the vastness of our great and immense. In what follows, we will focus our attention on it.

Dear reader can find additional information in the video in this article.

Elements

So, what elements does the water supply scheme of an apartment building include?

Water meter assembly

He is in charge of feeding the house cold water.

The water meter performs several functions:

• Provides accounting for water consumption (as its name unambiguously reminds);
• Allows you to turn off cold water for the whole house to repair shut-off valves or eliminate spill leaks;
• Provides coarse filtration of water at the entrance to the house. To do this, the water meter is equipped with a sump.

The composition of the water meter includes:

1. Entrance and house shut-off valves(gate valves or Ball Valves located on the side of the input of cold water supply and the intra-house water supply system);
2. Water meter (usually mechanical);
3. Gryazevik (tank with drain tap, in which, due to the slow movement of water through its volume, sand, large particles of rust and other debris settle). Often, instead of a sump, the water meter unit is equipped with a filter coarse cleaning, in which a stainless mesh is responsible for cleaning water from debris;
4. Pressure gauge or control valve for its installation;
5. Optionally, the water meter can be equipped with a bypass line with its own valve or a ball valve on it. The bypass opens when the water meter is dismantled for the period of repair or verification. At other times, it is closed and sealed by a representative of the organization - the water supplier.

It is curious: "Vodoset", or the organization replacing it, is responsible for the state of input of cold water up to the first flange of the inlet valve. The water meter is the responsibility of the organization serving the house.

Elevator node

The elevator unit, or heating point, also combines a number of functions:

• Responsible for the operation and regulation of the heating system;
• Provides a home hot water. Water (it is also the heat carrier of the heating system) is supplied to the domestic hot water system directly from the heating main;
• Allows, if necessary, to switch the hot water supply between the supply and return threads of the heating main. The changeover is necessary because in winter the flow temperature can reach an impressive 150°C, and the allowable maximum temperature hot water- only 75°С.

A short lecture on physics: water is heated above the boiling point without evaporating, thanks to overpressure in the heat pipe. The higher the pressure, the higher the boiling point of liquids.

A heart elevator node- water-jet elevator, through the nozzle of which hot and having more high pressure supply water is injected into the mixing chamber filled with return water. Thanks to the operation of the elevator, a large volume of water with a relatively low temperature passes through the heating system of the house; at the same time, the consumption of water from the supply is relatively small.

DHW tie-ins are located between the inlet valves and the elevator. There can be two of these tie-ins (one for supply and return) and four (two for each thread). The first scheme is typical for houses built in the 70s of the last century and older buildings, the second - for more or less modern buildings.

Why are additional inserts needed?

To answer this question, we need to jump ahead and study the water supply schemes in apartment buildings.

On cold water, a dead-end scheme is always used: the water meter goes into a single filling, that one - into risers that end with intra-apartment connections. Water moves in such a water supply circuit only during drawdown.

What's going on in the GVS?

In houses with two DHW tie-ins to the elevator unit, the same scheme is used.

However, it has two rather annoying drawbacks:

1. If there was no water intake for your riser for a long time, the water has to be drained for a long time before it heats up;

Note: if you have mechanical meters on your pipes, they will register the flow of water, ignoring its temperature. As a result, you will overpay a hundred or two rubles a month for a service that you actually did not use.

1. Towel dryers installed on the hot water pipes, which are also responsible for heating the bathroom, will only heat up when hot water is drawn in your apartment. And, accordingly, most of the time will remain cold. Hence - the cold and dampness in the bathrooms, often becoming the cause of the appearance of the fungus.

Elevator unit with four DHW tie-ins provides continuous circulation of hot water through two bottlings and risers connected by jumpers.

DHW operation is possible according to one of three schemes:

1. From the supply to the return pipeline. Such a hot water supply scheme for a multi-storey building is used only in summer, when the heating is turned off: a bypass between the heating mains would reduce the pressure drop across the elevator;
2. From feed to feed. This scheme is for autumn and spring with their relatively low supply temperature;
3. From back to back. So DHW is turned on for the period of cold weather, when the supply temperature exceeds the threshold 75 degrees.

Readers who have not forgotten the basics of physics will have a reasonable question: how is the pressure difference necessary for continuous circulation between two tie-ins in one thread provided?

Remember: water is constantly moving through the pipes between the inlet valves and the elevator. To create a pressure difference, it is only necessary to restrict the flow by an obstacle installed between the tie-ins. This role is performed by a retaining washer - a metal pancake with a hole in it.

Captain Evidence suggests: a significant restriction of the patency of any pipeline would interfere with the operation of the elevator unit, so the diameter of the retaining washers is a millimeter larger than the diameter of the elevator nozzle. That, in turn, is calculated by the organization (heat supplier) in such a way that the return temperature at the outlet of the heating point corresponds to the temperature schedule.

Bottling

Water supply spills are called horizontal pipes, passing through the basement or subfloor of the house, and connecting the risers with the elevator and water metering units. Filling cold water is always the same, bottling hot water in circulation system hot water two.

The filling diameter, depending on its material and the number of water consumers, varies from 32 to 100 millimeters. The latter value is clearly redundant; however, the water supply project for an apartment building had to take into account not only Current state pipelines, but also their inevitable overgrowing with deposits and rust. After 20-25 years of operation, the clearance of the pipe in cold water decreases by 2-3 times.

Risers

Each stand is responsible for vertical wiring water in apartments located one above the other.

The most typical scheme is one group of risers (cold water and hot water, optionally heated towel rails) per apartment; however, other options are also possible:

• Two groups of risers can pass through the apartment, supplying water to a bathroom and kitchen spaced over a long distance;
• Risers in one apartment can supply water not only to its residents, but also to neighbors behind the wall;
• On DHW, circulation jumpers can combine up to 7 risers from several apartments.

The typical diameter of cold water and hot water risers is 25-40 mm. The diameter of risers for heated towel rails and idle (without plumbing fixtures) circulation risers is usually smaller: they are mounted with a DN20 pipe.

In the circulation scheme of hot water supply, the jumpers between the risers can be located in the apartment on the top floor or taken out to the attic. Jumpers are equipped with air vents (Maevsky taps or ordinary taps), which allow bleed air that prevents circulation.

Eyeliners

Their function is to distribute water to plumbing fixtures inside the apartment. What is useful to know about water supply lines?

• Their typical size (for steel water and gas pipes) - DN15 (which approximately corresponds to an inner diameter of 15 mm). When replacing eyeliners with your own hands, it is advisable not to reduce their inner diameter - this will lead to a drop in pressure on all plumbing fixtures when parsing water on one of them;

• Since Soviet times, simple and cheap serial (tee) wiring has traditionally been used in apartments. More material-intensive collector requires, among other things, concealed installation eyeliner, which greatly complicates their further maintenance;

• With time throughput steel eyeliners drops noticeably, due to the notorious overgrowing with deposits. In such cases, the pipes are cleaned with a thin steel string or, quite simply, they are changed to new ones.

If you decide to replace eyeliners, we strongly advise you to opt for metal pipes. The instruction is associated with a fairly high probability of water hammer and deviations from the standard temperature in the DHW system: for example, if a forgetful locksmith does not switch the water supply from supply to return at the first frost, the water temperature can significantly exceed the maximum for any polymer pipes 90-95 degrees.

Which pipes can be used for water supply:

Faults

What violations in the operation of the water supply system can the owner of the apartment eliminate on his own? Here are some of the most typical situations.

Leaking valves

Description: leak on the stem of screw valves.

• Reason: partial wear of the oil seal or wear of the rubber sealing ring.
• Solution: open the valve knob as far as it will go. In this case, the thread on the rod will press the stuffing box from below, and the flow will stop.

Noise of cranes

Description: when opening a hot or (more rarely) cold water tap, a loud noise is heard and the mixer is vibrating. Alternatively, your neighbor's faucet may be the source of the noise.

Cause: a deformed and crushed gasket on a screw valve box in a half-open position causes a continuous series of water hammers. Its valve closes the seat in the mixer body with a frequency of fractions of a second. On hot water, the pressure, as a rule, is noticeably greater, so the effect is more pronounced on it.

Decision:

1. Turn off the water to the apartment;
2. Unscrew the problematic crankbox;
3. Replace the gasket with a new one;
4. Remove the chamfer from the new gasket with scissors. The chamfered face will prevent the valve from beating in the turbulent water jet in the future.

By the way: ceramic crankboxes are fully compatible with screw threads, and are devoid of the described problem.

Cold towel warmer

• Description: The heated towel rail in your bathroom is cold and does not heat up.
• Cause: if the water supply scheme of a residential apartment building uses continuous circulation of hot water, the air remaining in the jumper between the risers after the water is discharged is to blame (for example, for revision and repair of valves).
• Decision: climb up top floor and ask your neighbors to bleed air from the jumper between the hot water risers and heated towel rails.

If for some reason this is not possible, the problem can be solved from the basement:

1. Shut off the DHW riser passing through your apartment, to which your connections are connected;
2. Climb into the apartment and open the hot water taps to failure;
3. After all the air comes out of the riser through them, close the taps and open the tap on the riser.

Nuance: immediately after graduation heating season between the threads of the heating main there may be no pressure difference. In this case, the heated towel rails will be cold even if there are no air pockets in the risers.

Conclusion

We hope that our material has helped you to study the water supply of an apartment building: the water supply scheme described by us is the most common. Good luck!

Imagine an ordinary morning in one of the high-rise buildings in the sleeping area of ​​our beloved city: toilet, shower, shave, tea, brush your teeth, water for the cat (or in any other order) - and go to work ... Everything is automatic and without hesitation. As long as cold water flows from the cold water tap, and hot water flows from the hot water. And sometimes you open a cold one, and from there - boiling water!! 11#^*¿>.

Let's figure it out.

Cold water supply or cold water

local pumping station supplies water to the main from the water utility network. A large supply pipe enters the house and ends with a valve, after which there is a water meter.

In short, the water meter assembly consists of two valves, a strainer and a meter.

Some have additional check valve

and water meter bypass.

The water meter bypass is an additional meter with valves that can feed the system if the main water meter is serviced. After the meters, water is supplied to the house main

where it is distributed along risers that lead water to apartments on floors.

What is the pressure in the system?

9 floors

Houses up to 9 floors high have bottom pouring from bottom to top. Those. from the water meter through a large pipe, water leaves through the risers to the 9th floor. If the vodokanal is in a good mood, then at the input of the lower zone there should be approximately 4 kg/cm2. Given a pressure drop of one kilogram, for every 10 meters of water column, residents on the 9th floor will receive approximately 1 kg of pressure, which is considered normal. In practice, in old houses, the input pressure is only 3.6 kg. And the inhabitants of the 9th floor are content with even less pressure than 1kg / cm2

12-20 floors

If the house is higher than 9 floors, for example 16 floors, then such a system is divided into 2 zones. Upper and lower. Where the same conditions remain for the lower zone, and for the upper zone the pressure is raised to about 6 kg. In order to raise the water to the very top into the supply line, and with it the water rises up to the 10th floor. In houses above 20 floors, the water supply can be divided into 3 zones. With such a supply scheme, the water in the system does not circulate, it stands on a backwater. In a high-rise apartment, on average, we get pressure from 1 to 4 kg. There are other values, but we will not consider them now.

Hot water supply or DHW

In some low-rise buildings, hot water is connected in the same way, it stands on a backwater without circulation, which explains the fact that when you open a hot water tap, cold, cooled water flows for some time. If we take the same house with 16 floors, then in such a house the hot water system is arranged differently. Hot water, like cold water, is also supplied to the house through a large pipe, and after the meter it goes to the house main

which raises the water to the attic where it is distributed along the risers and descends to the very bottom into the return line. By the way, DHW meters consider not only the volume of lost (consumed) water in the house. These counters also count the temperature loss (hygocalories)

The temperature is lost when water passes through apartment heated towel rails, which play the role of risers.

With this scheme, hot water always circulates. As soon as you turn on the faucet, hot water is already there. The pressure in such a system is approximately 6-7 kg. on the supply and slightly lower on the return to ensure circulation.

Due to circulation, we get pressure in the riser, in the apartment 5-6 kg. and immediately we see the difference in pressure between cold and hot water, from 2 kg. This is precisely the essence of squeezing hot water into cold water in the event of a malfunction of plumbing fixtures. If you notice that you still have more pressure on hot water than on cold water, then be sure to install a check valve at the cold inlet, and control valves can be included in the hot water inlet, which will help equalize the pressure by about one digit with cold. Pressure regulator installation example

Hot water systems can be connected directly (in open systems heat supply) or independently through water heaters (in closed systems heat supply). The type of heat supply system (open or closed) is determined during design, and the choice of a particular system is determined by technical and economic indicators.

Direct connection to the supply and return pipelines (a). Hot water of the required temperature is prepared by mixing it with the help of a thermostat from the supply and return pipelines. In the thermostat, the pressure of the water coming from the supply pipeline is throttled to the pressure of the return pipeline (and its amount depends on the temperature of the water in the return pipeline). In accordance with SNiP 41-02-2003 "Heat Networks", the temperature of the heated water at the outlet of the water heater to the hot water supply system should be taken equal to 60 ° C. Therefore, at a temperature in the return pipeline above 60 ° C, the water is completely supplied from the return pipeline , and when the water temperature in it is below 60 ° C - from the return and supply; at a water temperature in the supply pipeline equal to 60 ° C, - completely from it.

At independent accession heating systems (6) leaks are replenished from the hot water supply system after the displacement unit. If the pressure in the return pipeline of the heating network is insufficient to supply water to the hot water supply system, a pressure regulator (backup pressure) is installed with a sufficient total pressure or a booster pump, which can also be a circulation pump. Circulation can be carried out using throttle washers installed on the return pipeline heating system(winter mode) and on the circulation pipeline ( summer mode). In the presence of a pressure regulator (backup), a throttle washer for winter regime do not install.

Direct connection of the hot water system (open circuit)

a - to the supply and return; b - to the supply and return pipelines with independent connection of the heating system;
c - to the return pipeline; g - to the supply pipeline;
1 - mud collector; 2 - temperature controller of mixed water; 3 — controller temperature sensor; 4 - water riser;
5 - circulation pipeline; 6 - elevator of the heating system; 7 - booster circulation pump;
8 - make-up water pipeline; 9 - heating water heater; 10 - circulation pump of the heating system;
11 — throttle washer; 12 - hot water heater; RR - flow regulator; RD - pressure regulator

Direct connection to the return pipeline is shown in fig. c. With a significant flow of water for hot water supply, p\u003e 0.3, the hot water supply system is connected only to the return pipeline, and the water is heated to the standard temperature in the water heater. Such connection makes it possible to reduce the misalignment of the heating system, since the amount of water intake will not affect the water flow in the heating system.

Direct connection to the supply pipeline is shown in fig. d. With this connection, part of the water is taken from the city water supply, heated in a water heater, then mixed with the help of a regulator with water taken from the supply pipeline of the network. The purpose of the scheme is to reduce the consumption of water for hot water supply at the CHPP. However, this loses the main advantage of a system with direct water intake - the protection of the system from internal corrosion. The addition of tap water will corrode the hot water supply of buildings. For this reason, the hot water supply system cannot be connected to the return pipeline to ensure circulation in it, as this will lead to corrosion of the heating network pipelines.

Independent connection with the inclusion of a hot water heater according to parallel circuit. The heating coolant (network water) branches into two parallel flows: one enters the water heater, the other enters the heating system. Therefore, such an inclusion is called parallel. The parallel circuit is used for very small thermal loads of hot water supply in relation to heating (r m< 0,2) или очень больших (р > 1,0).

Turning on a hot water heater in parallel

1 - mud collector; 2 - water heater; 3 - heated water temperature controller;
4 - circulation pump; 5 - distributing pipeline; 6 - water riser;
7 - circulation riser; 8 - circulation pipeline; 9 - heating system;
10 - flow constancy regulator; 11 - elevator

In the absence of storage tanks, due to the uneven consumption of hot water, significant flow fluctuations are observed network water, which affects the parallel connected heating system. Therefore, to stabilize the water flow in the heating system, a constant flow regulator is installed in front of it.

Independent connection with the inclusion of a hot water heater according to mixed scheme. The heating coolant (network water) branches into two parallel streams: one enters the II stage water heater, the other enters the heating system. From the heating system, network water enters the water heater of the 1st stage. heated tap water first, it enters stage I, where it is heated by the coolant supplied from the heating system and from the water heater of stage II, and then to stage II until it is heated to the required temperature.

Switching on a hot water heater according to a mixed scheme

1 - mud collector; 2 - temperature controller; 3 - water heater II stage;
4 - flow regulator; 5 - distributing pipeline of the hot water supply system;
6— circulation pipeline; 7 - circulation pumps; 8 - heating system;
9 - elevator; 10 - water heater of the 1st stage

Since one water heater is connected in parallel with the heating system (stage II), and the other in series, this scheme is called mixed. The mixed scheme is applied if p m => 0.2-1, if heat is supplied according to heating schedule or if the heating systems are equipped with elevators with adjustable nozzle. The mixed scheme is also used when connecting public buildings with a ventilation load of more than 15% of the heat consumption for heating. Here, as in the parallel scheme, there are fluctuations in the consumption of network water due to the uneven consumption of hot water. Therefore, to stabilize the water flow in the heating system (in the absence of heat release regulators on it), flow regulators are installed.

Independent connection with the inclusion of water heaters for hot water supply in series.

The heating coolant (network water) passes successively to the II stage hot water heater, then through the heating system and then to the I stage hot water heater. Heated tap water first enters stage I, where it is heated by the coolant supplied through the heating system, and then into stage II for heating to the required temperature. Thus, both hot water heaters and the heating system are connected in series.

The sequential scheme is used at a value of p m = 0.2 - 1 and heat is supplied according to the total load of heating and hot water supply ( increased schedule). A distinctive feature of the sequential scheme is the constant flow of network water in heating point, which makes it possible to maintain a stable hydraulic mode in the heating network. The set constant flow rate is maintained by the flow regulator, which changes the flow rate of network water at the jumper, depending on the flow rate for the period of hot water supply.

Turning on the hot water heater in a sequential scheme

1 - sump;, 6 - temperature controller; 3 - water heater II stage; 4 - flow regulator;
5 - distributing pipeline of the hot water supply system; 6 - circulation pipeline;
7 - heating system; 8 - circulation pumps; 9 - elevator; 10 - jumpers for the summer period;
11 - water heater of the 1st stage

There are three main schemes for connecting heat exchangers: parallel, mixed, serial. The decision to apply this or that scheme is made by the design organization based on the requirements of SNiP and the supplier of heat coming from their energy capacities. In the diagrams, the arrows show the passage of heating and heated water. In the operating mode, the valves located in the jumpers of the heat exchangers must be closed.

1. Parallel circuit

2. Mixed scheme

3. Sequential (universal) circuit

When the DHW load significantly exceeds the heating load, hot water heaters are installed at the heating point according to the so-called one-stage parallel scheme, in which the hot water heater is connected to the heating network in parallel with the heating system. The constancy of the temperature of tap water in the hot water supply system at the level of 55-60 ºС is maintained by the RPD direct-acting temperature controller, which affects the flow of heating network water through the heater. When connected in parallel, the consumption of network water is equal to the sum its expenses for heating and hot water supply.

In mixed two-stage scheme the first stage of the DHW heater is connected in series with the heating system on the return line of the heating water, and the second stage is connected to the heating network in parallel with the heating system. At the same time, tap water is preheated by cooling the network water after the heating system, which reduces heat load second stage and reduces the total consumption of network water for hot water supply.

In a two-stage sequential (universal) scheme, both stages of the DHW heater are connected in series with the heating system: the first stage - after the heating system, the second - before the heating system. The flow regulator, installed in parallel with the second stage of the heater, maintains a constant total flow of network water to the subscriber input, regardless of the flow of network water to the second stage of the heater. During hours of maximum DHW loads all or most of network water passes through the second stage of the heater, is cooled in it and enters the heating system with a temperature below the required one. In this case, the heating system receives less heat. This undersupply of heat to the heating system is compensated during hours of low loads of hot water supply, when the temperature of the network water entering the heating system is higher than required at this outdoor temperature. In a two-stage sequential scheme, the total consumption of network water is less than in a mixed scheme, due to the fact that it uses not only the heat of network water after the heating system, but also the heat storage capacity of buildings. Reducing network water costs helps to reduce unit cost external heating networks.

The scheme for connecting hot water heaters in closed heat supply systems is selected depending on the ratio of the maximum heat flow to hot water supply Qh max and the maximum heat flow to heating Qo max: