Two-pipe heating system is a proven and effective way to heat a private house. This system allows you to regulate the heating of any room without changing the temperature in the rest of the house. Two-pipe heating system can be used in houses of any number of storeys. The main feature of the two-pipe system is the separation of the forward and reverse coolant circuits. By feeding, the so-called pipe, the system receives heated water from the boiler, from which the coolant is analyzed into radiators, coils, and a system of warm floor. After passing through them, the cooled liquid is removed with the help of another pipe - the return one.
Two-pipe heating system for a private house
The two-pipe system has several advantages:
- Easy control of the flow of coolant in any of the radiators;
- Possibility of application in the house of any number of storeys;
- Possibility to mount systems of considerable length.
Among the disadvantages is the doubled number of pipes compared to the one-pipe system, which increases the cost of installing the system and reduces its aesthetics - the pipes of the direct current of water should be located above the level of radiators, they are usually laid under the ceiling or at the level of the windowsill.
Device and elements of the two-pipe heating system
The two-pipe system, as well as the single-tube system, can be executed with natural and forced circulation of the coolant. The choice of the type of circulation is usually affected by the selected type of wiring of the direct current pipe: upper or lower.
Upper wiring means laying a straight pipe at a significant height, which provides good pressure when passing the coolant through the radiators without installing the pump. The two-pipe system with the top wiring looks more aesthetically pleasing and allows the trunk pipe of direct current to flow through the entire building above the doorways, in addition, it can be covered with decorative elements. The disadvantage of such a system is the need to install a membrane expansion tank, which requires additional costs. It is also possible to install an open type tank, but with one condition - it must be installed at the highest point of the system, that is, in the attic. This, in turn, leads to additional expenses for the insulation of the tank.
With lower wiring, the feed pipe is located just below the window sill. In this case, there is no problem with installing an open-type expansion tank in a warm room - it can be installed anywhere above the level of the straight pipe. However, it becomes necessary to install a circulation pump, as well as the inability to pass pipes through the opening of the entrance door. If the boiler is installed in close proximity to the entrance to the house, the heating circuit is laid along the perimeter to the door. Otherwise, it is possible to divide the contour into two independent wings having their own straight and return tubes.
Diagram of a two-pipe heating system with pump circulation of water with a lower distribution of the supply pipeline
The circulation pump is installed in the return pipe, since the maximum temperature of the liquid of the unit does not usually exceed 60 degrees, and the coolant at the outlet of the boiler can damage it.
The location of the expansion tank depends on its type: a membrane-type tank with a closed chamber can be installed in any convenient place, it is usually placed next to the boiler. Open expansion tank is installed necessarily above the level of the straight pipe, this will help to avoid the formation of air bubbles in the system.
The diameter of the main pipes in a two-pipe heating system is usually 25-32 mm, but for an extended system it can be more than 50 mm. In this case, the pipe has a significant heat transfer, which must be taken into account when calculating the radiator sections.
Radiators attach one of the selected wiring diagrams. The most effective are the lateral and diagonal connection schemes, the bottom connection is used in rare cases for low-level radiators, with the main straight pipe placed above the radiator.
There are also some requirements for the installation of the boiler: for good circulation it is necessary that the coolant inlet from the return pipe be below its level. Therefore, the boiler is usually chosen for floor standing.
Features of a two-pipe heating system in a two-story house
If the heated premises of the first and second floors of the house are not divided among themselves by permanently closed doors, the heated air of the first floor will rise upwards, to the second floor. As a result, the microclimate of the house will be uneven: the bottom will be cool, and above - stuffy and hot. There are two ways to solve this problem:
- The heating of the second floor must be done with warm floors, not with radiators.
- Distribute the radiators so that 2/3 of the total number of sections of all radiators is on the first floor.
In addition, when planning a house, it is more rational to have rooms that need less heating: a kitchen, a living room, a library, and bedrooms and children's rooms should be arranged on a second, warmer floor.
Two-pipe heating technology
- Install a heating boiler with a capacity sufficient to heat all the premises of the house. It is recommended to install the boiler in strict accordance with the technical requirements.
- A special expansion tank is installed in a specially prepared place. If it is an open type tank, it should be placed above the highest point of the circuit, with an upper attic of the direct feed, an attic or attic room is suitable for this purpose. In the case of installing a tank in an unheated attic, it must be insulated and a signal pipe installed to prevent overfilling of the tank. The pipe is cut into the top of the tank and taken to the bathroom. Through it, you can drain excess coolant if necessary. The membrane tank can be placed anywhere above the floor level.
Connection example of a two-pipe heating system
- Mount a vertical straight riser to the highest point of the system, and then a straight pipe, ensuring a stable slope of 1%, i.e. 1 cm per 1 meter of length. For a straight pipe, the slope should be made away from the boiler. In the places of connection of heating devices, the pipe is connected by means of tees.
- Mount the return pipe. The installation is carried out along the same path as for the straight pipe, while starting it from the boiler. When installing, provide a similar bias towards the boiler, that is, the highest return point should be at the maximum distance from the boiler.
- Install the circulating pump in the return pipe, just before the boiler, if necessary.
- Mount and connect radiators or "warm floor" system with the necessary fittings.
Connection of radiators with
- fittings After successful crimping, the system is filled and test run of the boiler is performed. Regulate the supply of heat to the radiators with the help of cranes, checking the stability of the temperature for one or two days. Sometimes when filling the system, bubbling in pipes and batteries is observed. This is normal for an open tank system, if a diaphragm expansion tank is used, the drilling should stop after removing air bubbles from the system using Mayevsky cranes.
Video - Heating scheme for a private house
