Heating system of the house “Leningradka”

Recommendation points

Of the existing heating schemes, the simplest are single-pipe, in which radiators are connected in series. Among the main advantages are the minimum costs for pipes and fittings. One of the variations of one-pipe heating systems is popularly called “Leningrad”, which we will talk about in this article.

Heating system of the house

Despite the fact that only one of the varieties of one-pipe heating systems was called “Leningrad”, after a while all such types began to be called that. Interest is still aroused by the original version and its further development..

Features and Benefits

Any one-pipe connection scheme is good in terms of material savings and ease of installation. “Leningradka”, in particular, comes out on top for these characteristics. To understand this, it is enough to remember how she appeared.

In Soviet times, during the time of mass development, an ingenious and simple idea was born. The heating circuit was a solid pipe laid along the perimeter of the heated building along the outer walls and tied with the ends on the heating boiler. In the case of multi-storey buildings and vertical design, these were through risers.

Heating system of the house

One team laid the highway. The second brigade followed and cut radiators parallel to the main pipe. Radiators ran parallel to the line and in series one after another. A section of a common pipe between the outlets of one radiator formed a bypass.

With a serial connection, the coolant, reaching the last rooms, already significantly loses temperature, from which the heating in them significantly decreased. The presence of a bypass partly solves this problem..


  • minimum materials, low installation costs;
  • simple installation, passage of walls and ceilings with only one pipe;
  • the ability to adjust the uniform heat distribution.

Heating system of the house

Features include:

  1. In the presence of several circuits with special accuracy, it is necessary to match them according to the hydrodynamic resistance to water flow.
  2. Hot water enters the heat exchanger due to the temperature difference inside the radiator and the line. Therefore, you can get the maximum heat output only at an elevated temperature of the coolant and the presence of pressure.

Execution options

Depending on the orientation of the Leningradka highway, it happens:

  • vertical;
  • horizontal.


It is used for multi-storey buildings. Each contour constitutes a vertical riser extending from the attic to the basement on all floors. Radiators are connected by side connection parallel to the mains and in series on each floor.

Heating system of the house

The effective height of the “Leningrad” vertical type is up to 30 meters. If this threshold is exceeded, the distribution of the coolant is disturbed. It is impractical to use such a connection for a private house.


The best option for an autonomous heating system in a private house with one or two floors. The highway bypasses the building along the contour and closes to the boiler. Radiators are installed with a bottom or diagonal connection, with the upper point oriented towards the hot end of the line, and the lower point towards the cold end. Radiators are supplied with a Mayevsky valve for air release.

The circulation of the coolant can be:

  • natural;
  • compulsory.

Heating system of the house

In the first case, the pipes are distributed along the contour with a mandatory slope of 1–2 degrees. The hot outlet from the boiler is located at the top of the system, the cold one – at the bottom. To increase circulation, the section of the line from the boiler to the first radiator or the switch-on point of the open expansion tank is laid with an upward slope, and then evenly downward, closing the circuit.

System elements:

  • boiler (hot outlet);
  • open-type expansion tank (upper point of the system);
  • heating circuit;
  • a branch pipe with a ball valve for draining and filling the system (the lowest point of the system);
  • ball valve;
  • boiler (cold lead).

Heating system of the house 1 – heating boiler; 2 – open-type expansion tank; 3 – radiators with bottom connection; 4 – Mayevsky crane; 5 – heating circuit; 6 – valve for draining and filling the system; 7 – ball ventile

There is no need for a one-story house to make the upper and lower wiring of the highway, the lower wiring with a slope is enough. The coolant circulates mainly along the contour of the common pipe and the boiler. The hot coolant enters the radiators due to the pressure drop caused by the water temperature drop.

The expansion tank provides the required coolant pressure in the system. The open-type container is installed under the ceiling or in the attic. A membrane-type tank for a closed heating system is installed on the return line after connecting parallel circuits, but before the boiler and pump.

Forced circulation is preferable. There is no need to observe the slope, it is possible to carry out hidden installation of the main pipe Diaphragm expansion tank allows precise setting of system pressure.

System elements:

  • boiler (hot outlet);
  • five-way fitting for connecting a pressure gauge, air vent and explosive valve;
  • heating circuit;
  • a branch pipe with a ball valve for draining and filling the system (the lowest point of the system);
  • expansion tank;
  • pump;
  • ball valve;
  • boiler (cold lead).

Heating system of the house 1 – heating boiler; 2 – security group; 3 – radiators with diagonal connection; 4 – Mayevsky crane; 5 – expansion tank of membrane type; 6 – valve for draining and filling the system; 7 – pump

System Setup

The main problem of the one-pipe connection diagram of the Leningradka radiators is in adjusting the uniform distribution of the coolant over the radiators throughout the entire circuit. Most of the heat is released on heat exchangers closer to the boiler inlet. So even if the room borders on the boiler room, but is powered by the latter, it may be without proper heating..

There are three types of turning on radiators:

  • with a constant cross-section of the common pipe;
  • with a decrease in the diameter of the pipe sections between the branches to the radiators;
  • using needle valves at each bypass section.

Heating system of the house

For each radiator, it is advisable to install ball valves with two on / off positions on both inputs.

The version with a constant diameter is relevant for heating with natural circulation and nothing more. When using a pump, it is better to dwell on one of the other two switching schemes..

Selection of pipe diameter

If the bypass is made with a smaller pipe diameter than the main, then its resistance will be higher and more hot coolant will pass through the heat exchanger, giving off heat to the air in the room.

Due to the availability of a standardized range of pipe cross-sectional sizes, it makes no sense to perform a detailed calculation, selecting the optimal distribution of the coolant. It is important to choose the optimal diameter for the main pipe, based on the flow rate of the coolant. One size smaller will be the upper limit of acceptable values. The lower limit is the diameter of the pipe for connecting the radiator.

Heating system of the house 1 – bypass 1 inch; 2 – main pipe 1.5 inches; 3 – radiator connection pipe? inch

If the line is selected in the size of 1.5 inches, and is used to connect the radiator? inches, then the bypass can be made from a pipe? or 1 inch. For even distribution, the first third of the radiators are connected without changing the cross-section, and then with a reduced bypass diameter.

With valves

If there are several heating circuits, needle valves are installed to balance each of them before combining to a common return. It is allowed not to install a valve on a circuit with a maximum resistance of a greater length.

Heating system of the house

If you install a needle valve on each bypass, you can adjust the amount of coolant passing through the radiator within any permissible limits. This is the most effective way to set up “Leningrad” for heating a private house.

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