Connecting a heating radiator to a two-pipe system: choosing the optimal connection option

A heating circuit design with two pipes, supply and return, has a lot of advantages over an analogue with a single coolant circulation line, so it is often used when organizing heat supply.

There are several ways to connect a heating radiator to a two-pipe system. The supply method affects the efficiency of heat transfer of the battery, so its choice should be given special attention.

In the article, we outlined the pros and cons of a two-pipe heating system, described the specifics of different pipeline connection schemes, and also provided recommendations for choosing the optimal supply option based on the type of radiator and the characteristics of the room.

What is good about a two-pipe scheme?

Existing heating systems are divided into three groups - single-pipe, two-pipe and collector. The cheapest option to implement is the first option. However single pipe system the least effective in terms of adjustability of heat transfer in rooms and thermal energy consumption.

The maximum effect in terms of these indicators is achieved by a scheme with heating manifold. But it will also cost the most to create. An analogue with two pipes occupies a certain middle ground between them in cost and performance characteristics.

A two-pipe system is much more efficient than a one-pipe system, and with proper design, installation costs only 10–25 percent more than it does.

In a heating system with two independent pipelines, through one of them the coolant, most often water, is supplied to the radiator, and through the other it is discharged. As a result, each battery in the circuit receives almost the same amount of heat to transfer it to the room.

In a single-pipe analogue, the coolant is supplied to the radiator and discharged through one common heating pipeline. In this case, the first room heater from the boiler (boiler) receives much more thermal energy than the last one in the chain. And it turns out that the room farthest from the water heater is always cool, and the room closest to it is too hot.

The basic visual difference between these systems is the presence of a bypass in the single-pipe distribution next to the battery. This jumper ensures uninterrupted coolant circulation when one of the radiators needs to be completely or partially disconnected from heating. In a heating circuit with two pipes it is simply not needed.

Among the main advantages of using a two-pipe system:

• accuracy of heat transfer adjustment in individual rooms;
• versatility - suitable for any home;
• independent operation of individual radiators from the rest;
• possibility of quick installation of additional batteries.

However, efficiency comes at the price of increased length. heating pipes. Each radiator in such a system is supplied with a pair of pipelines with coolant from the boiler - one for supplying heated water, the second for return.

A common mistake when choosing between one-pipe and two-pipe schemes is that the second option is estimated to be one and a half to two times more expensive than the first, which is absolutely not true

If there is only one pipe, then in the project it is laid out wider in cross-section than with a two-pipe distribution. As a result, the total cost of these two options in terms of materials does not differ so much.

But the volume of installation work actually doubles. If you do the installation yourself, then this point is not so relevant. However, if you order the assembly of the system externally, you will have to pay a little more for a circuit with two pipelines. But it will definitely not be twice as expensive.

Piping connection points to the battery

Before choosing a method for connecting a radiator to a water heating system, you must carefully examine the heating device itself.

It consists of a pair of horizontal collectors connected to each other by vertical jumpers. On top of this entire structure is a “casing” in the form of a heat exchanger with the maximum possible area of ​​​​contact with the air around it.

A classic aluminum, steel, bimetallic or cast iron radiator has four pipe connections, but there are also options with only two pipes

To connect the device in question to any pipe heating system, only an inlet and an outlet are required. Manufacturers make four connection points in the radiator for the sake of versatility. So the battery can be connected in any of the existing ways, simply closing the two remaining inputs and outputs with plugs.

The connection pipes for heating pipes in the radiator are located on the side or bottom. Side connection is more practical and most common.

The lower analogue is usually chosen for aesthetic reasons. With it, pipelines can be mounted in the floor, making them completely invisible.The result is a more beautiful interior.

In radiators with connectors for pipes at the bottom inside, there is a special jumper that forces the coolant to circulate throughout the entire area of ​​the heater, and not go directly to the return outlet without releasing heat

There is no fundamental difference in heat transfer between the “side” and “bottom” radiators. What is more important here is the method of connecting the pipelines with the relative position of the supply and return lines relative to each other.

In this case, it is recommended to connect devices with pipes from below only in systems with forced circulation of coolant, but not natural delivery. In the second case, it will be too difficult for the heated water to rise up from the inlet and heat the battery.

Radiator connection methods

The heat transfer efficiency of the radiator directly depends on the choice of heating piping connection scheme. If the coolant does not circulate throughout its entire internal area, but quickly exits into the return line, then the battery releases heat to a minimum.

The most effective connection method is diagonal. With it, the water inside the radiator has time to cover all sections on the way from the entrance to the exit, giving off thermal energy to each

There are three ways to connect pipes with coolant to the radiator:

• lateral one-sided — the pipes are located on the side on one side;
• horizontal - lower or upper - the pipes are at the same level horizontally relative to each other on top or bottom of the battery - one fits on the right, and the second on the left;
• diagonal cross — pipes are connected diagonally.

In radiator data sheets, heat transfer is usually indicated for the diagonal connection method.With a side connection, heat loss will reach 10% of this maximum. And with the horizontal option they can reach all of 20–25%.

However, much here depends on the number of sections and the internal structure of the battery. Plus, the material used to make the radiator, as well as its location in the room, plays an important role.

For more information on selecting batteries, see this article.

Pipeline layouts for coolant supply are:

• with top supply;
• with bottom inlet.

If the system is with natural circulation, then a scheme with top wiring will be more efficient and preferable. But if available circulation pump Both options are acceptable.

Directly radiator connection process It doesn’t depend much on the method of supplying the heating pipes. The supply and return are connected to the battery in accordance with the selected circuit. And the remaining two holes are closed with a Mayevsky tap and a plug.

Option #1 - with top wiring

In this scheme, the coolant line approaches the radiator from above. The outlet pipe can be connected on the same side, in the side version, or on the other (diagonal analogue). In this case, the movement of water in the supply and return circuits can be either forward or counter (dead-end).

If there are fewer than ten sections in the radiator, then the lateral method of connecting the pipes is almost as good as the diagonal one - but if there are more of them, the coolant will reach the edge of the battery farthest from the entrance only with strong pressure in the system

When choosing an upper connection, it is recommended to organize the movement of the coolant according to a parallel scheme.In this case, the return and supply circuits are approximately the same length, which greatly simplifies the balancing of the entire system.

The diagonal method of connecting pipes with an upper coolant supply is considered the most effective. However, with proper design, the other options are also quite applicable. And, often, they also turn out to be more affordable. In this case, all the work can be done independently.

In practice, a dead-end scheme is more often used, since it requires slightly smaller pipes.

If the house is small - up to 200 sq. m and want to save as much as possible on the heating system, you should prefer a scheme with counter-movement of heated water. Here the adjustment is not so complicated and quite feasible. But for a large cottage - two to four floors, it is better to choose something else.

Option #2 - with bottom supply

In this case, the coolant is supplied from below. If such wiring is built in a one-story house, then this allows you to get rid of risers. Both pipes are laid from the boiler along the floor and do not disturb the interior with their appearance. The fewer pipelines there are in a room, the more beautiful everything looks.

The main advantage of the lower supply is the absence of risers, which slightly reduces the amount of the estimate for installing a heating system in the house

The return line can be connected in the following scheme:

• side;
• horizontally from below;
• diagonally.

If a regular radiator is used, without a special partition for more efficient circulation of coolant inside, then it is best to choose a diagonal connection method.

However, the hydraulic resistance in this case is greater than with the horizontal version. Here you need to carefully consider what is more profitable when doing thermal calculation.

Often the horizontal method is the most efficient in terms of heat loss. But this is only possible if there is a plug at the inlet between the first and second sections of the battery, which directs the coolant upward throughout the radiator. This way the resistance is minimal and the heat transfer is maximum.

It is recommended to choose the bottom supply only for circulation heating systems. With the natural movement of the coolant, air will constantly accumulate in the radiators, especially with horizontal and lateral pipeline connections.

It will have to be constantly lowered with help Mayevsky cranes. And these are additional body movements, so it is better to initially rid yourself of such worries.

Conclusions and useful video on the topic

How to connect a radiator in a two-pipe system:

The nuances of connecting the battery to the coolant supply and return:

Installation of a radiator in a heating system with two pipes:

When connecting radiators, the main thing is not to forget to install thermostats on both pipelines to accurately balance the home heating system. But it’s even more important to make a good thermal calculation for a specific cottage with the correct choice of pipes in cross-section and number of sections.

It is better to delegate this moment to a professional. Otherwise, you will have to overpay for extra pipes and radiator space, or then add new elements to the system.

Share with readers your experience of connecting radiators to a two-pipe heating system. Please leave comments, ask questions about the topic of the article and participate in discussions - the feedback form is located below.