Two-pipe heating system: scheme

If you refuse to use inefficient centralized heating in favor of an individual system, it can be difficult for the owner of the apartment to decide which is better: one-pipe or two-pipe heating system. We will find out what type of system is better to choose for installation, what is the difference between these connection schemes and how significant it is.

Advantages and disadvantages of single-pipe and two-pipe heating systems

The main difference between the two heating circuits is that the two-pipe connection system is more efficient in operation due to parallel arrangement of two pipes, one of which delivers the heated coolant to the radiator, and the other - removes the cooled liquid.

The scheme of a single-tube system is a serial wiring, in connection with which the first the connected radiator receives the maximum amount of thermal energy, and each subsequent one heats up ever weaker.

However, efficiency is an important, but not the only criterion on which to rely, when deciding to choose one or another scheme. Consider all the pros and cons of both options.

Single pipe heating system

Benefits:

• simplicity of design and installation;
• material savings in connection with the installation of only one highway;
• natural circulation of the heat carrier, possible due to high pressure.

Disadvantages:

• complex calculation of thermal and hydraulic parameters of the network;
• the difficulty of eliminating design errors;
• all network elements are interdependent, in case of a malfunction of one network section, the entire circuit ceases to work;
• the number of radiators on one riser is limited;
• adjustment of the flow of coolant into a separate battery is not possible;
• high coefficient of heat loss.

Two pipe heating system

Advantages:

• the ability to install a thermostat on each radiator;
• independence of the work of network elements;
• the ability to insert additional batteries into an already assembled line;
• simplicity of elimination of errors made at the design stage;
• to increase the volume of coolant in heating devices, it is not necessary to add additional sections;
• the absence of restrictions on the length of the contour along the length;
• the coolant with the desired temperature is supplied along the entire ring of the pipeline, regardless of the heating parameters.

Disadvantages:

• a complex connection scheme compared to a single pipe;
• higher consumption of materials;
• installation requires a lot of time and labor.

Thus, a two-pipe heating system is in all respects preferable. Why do the owners of apartments and houses refuse it in favor of a one-pipe scheme? Most likely, this is due to the high cost of the installation and the high consumption of materials necessary for laying two highways at once. However, it should be noted that the two-pipe system involves the use of pipes of smaller diameter, which are cheaper, so the total cost of arranging a two-pipe option will not be much more than a single-pipe one.

Owners of apartments in new buildings were lucky: in new houses, in contrast to Soviet-era residential buildings, a more efficient two-pipe heating system is increasingly used.

Types of twin pipe systems

Two-pipe systems are divided into types depending on:

• type of circuit (open and closed);
• method and direction of water flow (flowing and dead ends);
• a method of moving the coolant (with natural and forced circulation).

Open and Closed Loop Systems

The open-type two-pipe system in urban apartments did not take root due to the peculiarity associated with the upper pipe layout, which involves the use of an expansion tank. This device makes it possible to control and replenish the heating system with water, but the apartment does not always have a place for mounting such a volumetric device.

Flowing and dead end

In a flow system, the direction of the flow of water in the supply and outlet pipes does not change. With a deadlock, the coolant in the supply and return pipes moves in opposite directions. In such a network, bypasses are installed, and radiators are located in closed areas, which makes it possible to turn off any of them without disturbing the operation of the heating.

With natural and forced circulation

For natural water circulation, pipes are laid with a mandatory slope; an expansion tank is installed at the top of the system. Forced circulation is carried out by a pump installed in the return pipe. Such a system requires air vent valves or Mayevsky taps.

Two-pipe individual heating system components

The two-pipe scheme of the individual heating network of the apartment includes the following elements:

• heating boiler;
• thermostatic valves for radiators;
• automatic air vent valve;
• balancing device;
• pipes and fittings;
• radiators;
• valves and taps;
• expansion tank;
• filter;
• temperature gauge;
• circulation pump (if necessary);
• safety valves.

Installation of a two-pipe heating system with upper and lower wiring

The two-pipe system has varieties according to the installation scheme. The most commonly used top and bottom wiring types.

Top wiring

Laying the upper wiring involves installation work to fix the heating system under the ceiling of the room. The batteries installed in places of accumulation of cold air (window openings, balcony doors) are supplied with branches coming from the main pipeline. Liquid enters the lower part of the pipeline, which is a bypass, which manages to cool down during the circulation process. Such a system is suitable for large rooms, in one-room or two-bedroom apartments, a heating installation with top wiring is not recommended, as it is economically and from a design point of view disadvantageous for the owner.

Installation of the heating circuit with the upper horizontal wiring is performed according to the following scheme:

1. The corner fitting required to connect the pipe pointing upward is mounted to the boiler outlet.
2. Using tees and angles, horizontal installation of the upper line is carried out: tees are installed above the battery, angles are on the sides.
3. The final stage of the installation of the upper horizontal is the installation of tees with nozzles on the battery, supplemented by a shut-off valve.
4. On the lower branch, the outlet ends are connected to a common return line, in the area of ​​which a discharge pump station (circulation pump) is installed.

Bottom wiring

In a network with a lower wiring, outlet channels and supply heat-conducting pipes are mounted. The superiority of the bottom mounting scheme is expressed in the following:

• Heating pipes are located in the lower, inconspicuous part of the room, which gives more opportunities for the implementation of various design projects.
• Minimum consumption of pipes: all installation work is carried out almost at the same level. The wiring point and radiator pipes are located a short distance from each other.
• Due to the simplicity of the scheme, the installation of such a system will be possible even for a layman.

Important! The lower wiring is mounted only if the coolant will be forced to circulate, otherwise the water will not move through the heating pipes. This scheme is applicable exclusively to urban apartments or single-story buildings.

One of the drawbacks of the circuit is the difficulty of adjustment and balancing, but the simplicity of installation and reliability in operation overcome these disadvantages.

1. Installation work begins with the outlet from the boiler nozzles using an angled fitting in the downward direction.
2. The wiring is carried out at the floor level along the wall using two pipes of the same diameter. One of them connects the boiler nozzle to the battery inlet, the other leads to the receiving pipe.
3. Connections of radiators with pipes are performed using tees.
4. The expansion tank is located at the highest point of the supply pipe.
5. The end of the outlet pipe is connected to the circulation pump; the pump itself is located at the entrance to the heating tank.