Radiation is the piping layout in centralized heating. It is used, as a rule, in apartment buildings. Radiant heating also finds application in multi-storey private mansions and cottages, as well as commercial buildings.
The device and principle of operation of the radiant heating system
Unlike one-pipe and two-pipe connection schemes, where radiator batteries are connected in series and form a single pipeline, with a radial heating scheme, each radiator is connected by a separate pair of pipes and they all converge in a manifold — a single pipeline assembler.
The scheme of a radiant heating system implies the presence of an inlet pipe that supplies the coolant and a return pipe, through which the latter returns to the boiler.
The radiant heating system is convenient because the pipes are hidden under the floor and do not spoil the interior design with their presence. The collector is recessed into the niche of the wall. As an alternative, a neat collector cabinet can be mounted for it, which is usually decorated in the color of the finish and looks attractive.
Note! It is important that there are no connecting and especially shut-off fittings in the part of the system hidden from prying eyes. All of them should be located in a cabinet or on a radiator, that is, in places accessible for maintenance.
Like any steam-water heating system, the radial one also begins with a boiler and an expansion tank. For the device, its preference is given to indirect heating boilers, the distinguishing feature of which is that the coolant in them is located outside the boiler (in pipes), and the heating medium in the form of steam or water is in the latter’s tank. Hence the name of the room in which the water heater is installed — boiler room.
On a note! Now the term «boiler» has become synonymous with any storage boiler. But it is worth knowing that technically this is not always true.
When installing a beam system, instrumentation is installed on the boiler, but most of them are mounted in the collector, where temperature, water flow and pressure are monitored in each individual beam.
The collector-beam wiring diagram can be single-circuit and double-circuit. A single-circuit heating system means a cycle of water movement from the boiler to the radiator and back along the return line. The double-circuit system, in turn, is a radiator heating combined with hot water supply or radiator heating, working in tandem with the “warm floor” system.
Note! Given the extensive network of the beam system, consisting of several collectors and a fairly significant number of pipes connected to them, we can talk about a multi-circuit system, where each collector is a separate circuit.
All of the above makes it mandatory to install hydraulic switches or hydraulic separators that will protect the boiler and the entire heating complex. They are usually installed at the outlet of the boiler, and in multi-circuit assembly — in front of the collectors. The circulation pump also plays an important role in the operation of the heating system with a radial wiring diagram. And this should be taken into account during installation.
In the photo — a hydraulic arrow, designed for several circuits.
How is a collector-beam system different from others?
In centralized heating systems, the following piping schemes generally operate:
- One-pipe scheme, nicknamed «Leningrad». This wiring option continues to be used in small private houses with a minimum number of heated rooms. Leningradka is valued for ease of installation and minimal consumption of materials.
- Two pipe system. It is called the Tichelman loop. Its installation is complicated by the presence of doorways, balcony doors and floor-to-ceiling windows. These obstacles force the installation of additional pipes, which increases the consumption of materials.
The mentioned systems are assembled with a tee or perimeter connection, which has one serious drawback. The fact is that if any one node fails, for repairs it is necessary to stop the entire system, which is especially difficult when it is winter outside.
The collector-beam heating system is devoid of the disadvantages inherent in the Tichelman loop and single-pipe systems. Its main difference from single-pipe and two-pipe connection schemes is that each battery has its own line and is not fastened to the adjacent battery. All pipes in the collector converge like rays, which is obvious from the name.
Key advantages and disadvantages of a radiant heating system
Radiant heating has its advantages and disadvantages. The advantages include:
- Ease of installation that does not require high qualifications. Any private developer who has basic knowledge of plumbing can assemble such a system for himself;
- Reliability. The simpler the installation and the fewer connecting elements in the circuit, the stronger it is. Thus, reliability is another significant advantage of the beam scheme;
- No additional costs when transferring the media;
- Ease of maintenance. This is another factor that makes the radiant heating system attractive, the scheme of which is quite reasonably popular;
- Autonomy of each beam (each individual object). In other words, in order to repair any one section of the heating system, it is not necessary to block the entire system. It is enough just to drown out only the repaired link, while the rest will continue to work. Autonomy with a beam scheme also allows you to control the temperature in each individual link and room.
Control of coolant flow in each individual link. Now each individual consumer can only pay for their own consumption of heat energy and refuse to pay if the supplier does not provide the housing with heat in full. This factor is key in choosing a beam system for multi-family buildings.
The disadvantage of the beam system in this case can be called the material consumption of this piping scheme, since a separate pipeline is required for each individual section. However, material costs are quickly offset by energy savings and comfort when using the heating system.
Main structural elements
Like any heating system, a radiant heating scheme begins with a boiler. It is followed by an expansion tank, a piping system and a pump. With the device, one cannot do without control and measuring instruments, which are represented by: thermostats, pressure gauges, water flow meters and other elements. But unlike other systems, a collector appears in the beam pipe connection scheme, which is why the latter was called collector-beam.
On a note! Each user chooses a boiler for mounting a beam system, depending on the availability of the energy carrier. Solid fuel boilers run on wood, coal and peat. A gas boiler is installed if gas is supplied to the house.
Selection and installation of a circular pump
The radiant heating system stands out among the rest by the available methods of coolant transfer. There are 2 main ways in total:
- Gravitational, or natural. With this method, water moves due to the difference in density between the cold and hot liquid. Cold has a higher density, it is heavier, and therefore rushes down. When laying pipes for organizing natural circulation, it is necessary to take into account the slope for gravity flow. The possibilities of free movement of the coolant remain limited, and therefore developers who install heating according to the beam scheme prefer forced circulation.
- The forced movement of water in the radiant heating circuit is created through the use of circulation pumps. It should be noted that the pumps significantly expand the potential of the collector system, without limiting the installation of heaters either in quantity or in the distance between the collector and radiators.
When installing natural circulation, the coolant starts to move only when there is a significant temperature difference in the supply and return pipes, which affects the overall air temperature in the heating system and leads to increased consumption of the following energy sources:
- gas, if a gas boiler is installed;
- electricity during the operation of the electric boiler;
- coal or firewood, when using a solid fuel unit.
Forced circulation makes the coolants move faster, preventing the water from completely cooling down. This saves energy.
When installing a system with forced circulation, there are some nuances that you should be aware of:
- Clean water pumps are installed in heating systems. But they are quite sensitive to solid particles. Therefore, before installing and connecting the hydraulic pump, it is necessary to flush the piping system so that it is free of solid particles and dirt. Also, a filter should be installed in front of the pump at the inlet to prevent contamination.
- When installing the pump, it is important to ensure that the impeller is directed in the direction of water movement. If the pump is installed on the supply, then its impeller must direct the coolant towards the radiator; and if the pump is installed on the return, then the movement of water is directed towards the boiler. The pump housing always has an arrow pointing in the direction of flow.
- Household pumps operate on voltage 220-230V. When installing the device, it is desirable to arrange a separate power supply line for it. The connection is made in the presence of 3 wires: zero, phase, ground.
The figure shows the connection diagram of the circulation pump.
For a private house, it is better to choose a pump with a wet rotor, that is, one in which both the impeller and the rotor are in the water, and the starter and other electrical elements are sealed. With a low efficiency of 50%, wet rotor pumps are not capricious, they do not require additional maintenance and operate for 5-10 years. Such electrical appliances are preferred in private homes, but can be used in other types of buildings.
In the figure: the pump is installed in the return line of a warm floor.
Dry rotor pumps provide high efficiency — up to 80%. But they require the installation of special filters, additional regular maintenance by specialists.
Such products are operated, as a rule, no more than 3-5 years. These pumps are more suitable for multi-storey buildings than private houses. If only because in the first, scheduled overhauls are carried out relatively often.
On a note! The performance of the pump is selected according to the power of the boiler. For example, if the boiler has a power of 6 kW, then the pump capacity should be 6 l / min.
The choice and role of the distribution manifold
The collector, which among specialists has received the name of a comb, acts as a distribution device for dividing the coolant between heat consumers.
This device is a pipe with threaded fittings built into it, because of which it received the name of a female hair accessory.
All pipes from radiators or elements of a water-heated floor are connected to the collector. On the comb, thermostatic, shut-off and control, measuring instruments are installed, which generally control the flow of the coolant while maintaining the optimum air temperature in the heated rooms. Air extractors from each circuit are also built in here.
In multi-storey and apartment buildings, collectors are installed on each floor. To give greater aesthetics, as well as to protect equipment, special cabinets have been developed for distribution systems. The best option is when special niches for such cabinets are provided in the architecture of the building. But their installation is also possible outside, and in any place suitable for this, so even if they are not in the project, installation will not be a problem.
On a note! Cabinets for collectors, as a rule, have compact dimensions, they do not take up extra space, they are distinguished by functionality and practicality.
When choosing a collector, consider:
- The material from which it is made. For the heating system, it is better to buy collectors made of stainless steel or brass.
- The number of consumers and their correspondence to the number of nozzles. It is allowed to install a collector with one extra element, no more.
- Comb type. There are radiator and clamping ones. The latter are also used in heating systems less often than the former.
If the same radiators with the same number of fins are installed in the system, a radiator manifold will do. On the nozzles of such combs, ball valves are installed that work to open and close. This is the simplest type of combs.
Clamping combs are mounted if the heating devices in the radiator system differ in type, volume of coolant consumed and power. Such combs differ from radiator ones in the presence of adjusting screws that are installed on top or on the side.
Note! The more the adjusting screw is screwed (closed), the less coolant enters the circuit. Adjusting screws balance the heat supply. For a more even distribution of the coolant between the batteries and the underfloor heating, the supply of coolant to the pipes leading to floor heating is reduced.
It would be appropriate to install a sump with a filter mesh in front of the collector. This device will increase the length of the comb and, thereby, help to distribute the coolant between the nozzles more evenly. But the most important thing is that this element will not allow dirt to enter the pipes, as well as the collector.
On a note! Another significant advantage of the sump is the ease of disassembly before washing the filter mesh, which can be done by almost everyone.
In the picture: a collector-beam heating system with inlet and outlet combs.
Beam wiring connection diagram
Installation of a radiant heating system is available to anyone who has locksmith skills and knows how to hold tools in their hands. For work you will need:
- adjustable or gas key;
- electric drill with pobedit drills;
- pipe cutter for plastic and metal-plastic pipes;
- manual or hydraulic pipe bender;
- calibrator for preparing pipes for putting on fittings and connecting with each other;
- soldering iron for plastic pipes;
Before starting the installation of a radiant heating system, it is necessary to create its project, which indicates the location of the radiator batteries, their number, as well as the number of blocks in each battery, taking into account their heat transfer.
Even during the design process, it is necessary to calculate the number of pipes supplied to the radiators, consider the location of the collectors, and also plan the route for laying networks, and only then can one begin to calculate their length.
On a note! On the eve of installation, it is necessary to choose the most suitable collectors. Manufacturers produce combs with the number of nozzles from 2 to 12. Combs with the maximum number of nozzles are used, as a rule, in multi-storey buildings.
Depending on the size of the house and the number of radiators, the power and volume of the boiler are calculated. Then you have to calculate the number of fittings and valves. Do not forget that you will also need to buy valves to bleed air from the system.
Installation of radiant heating in an apartment or in a private house usually begins with radiator batteries. Using a laser level, the height of the radiators is marked and, in accordance with the selected indicator, holes are drilled for their fastening. The batteries are then suspended and levelled. Moreover, the latter is performed both in height and in distance from the wall. Simultaneously with the batteries, a collector is also attached, consisting of two combs: for hot water and for return. Thus, if 6 radiators are installed in the room, then two combs with 6 pipes each will be required.
In the picture: a collector with measuring instruments.
The next step is pipes. It is recommended to put on corrugated sleeves of a slightly larger diameter on these products before fastening in order to reduce heat loss. For installation, they are laid guides and only then the pipes themselves are laid.
Note! Guides are special devices with cells into which several pipes are inserted. Cells, fixing them, prevent displacement, they form a direction for their turn at the right angle and in the required direction.
Pipes can also be fixed with a special fixing tape, which is attached to the floor with brackets or self-tapping screws.
Remember: the pipes that are laid from the collector to the radiator must be solid, without joints. This can be achieved by buying them by the linear footage in tubes and subsequently cutting them along the length from the collector to the radiator. The desire to save money by connecting the tubes to each other with fittings will eventually result in a leak and the need to open the floor.
When all pipes are laid, they are adjusted for connection to radiators. At the same time, connecting fittings are mounted to the batteries, which have a square at the end, to which the pipes are connected at the end. Each battery has two ends: the first one is with the coolant and the second one is for the return flow.
When the pipes are fitted and connected, fasteners are screwed to the floor, fixing them completely. Next is the connection of pipes to the collector. In the assembly process, when connecting fittings, tow is used as a sealant, as the material most resistant to temperature extremes.
Radiation system and underfloor heating
The steam-water warm floor is perfectly integrated into the beam connection system. This design of the heating system is of particular importance on the ground floor of any building, whether it has two floors or 20. By installing a “warm floor”, you can increase the heating efficiency by 20-25%, so if you have such an idea, then you should not give it up .Moreover, the installation process is not as complicated as it might seem at first glance.
Well, we have prepared for you some practical tips that will come in handy when installing a warm floor built into radiant heating:
- A thermal mixer with American nuts is installed on the pipe connecting the radiator comb with the underfloor heating comb. This device will balance the thermal energy between radiators and underfloor heating. A thermal mixer is a consumable device that requires systematic cleaning, repair or replacement. And to remove it, it will be enough to unscrew the American.
- Before laying a warm floor on the screed, the concrete coating is insulated with an insulating layer of foil polyethylene. A reinforcing mesh is laid on top of the insulation. It will serve as a base when pouring the screed, and pipes of a water-heated floor are attached to it with wire.
- For installation of the system, a metal-plastic or plastic pipe made of cross-linked polyethylene with a diameter of about 15 mm is used. These pipes are preferred because, firstly, they keep the temperature well, and secondly, they are plastic and easily bent.
- Some masters do not recommend using stainless steel and polypropylene pipes in a warm floor. The latter are not resistant to high temperatures, they are characterized by increased fragility. They have a high coefficient of expansion and are not as flexible as XLPE or MRP, which are sold rolled up in tubes. In addition, the operation of polypropylene is allowed at temperatures not exceeding 90 ° C.
Features of installing a system for wooden houses
In a wooden house, both the subfloor and the finish floor are made of wood. And this carries its own design features when installing a heating system. During wiring, the pipes lie on the beams and logs across, and so that during the laying of the main floor boards they do not interfere, do not stick out and are not clamped, holes for pipes should be drilled or milled in the logs. These holes should be 3-5 mm larger than the diameter of the pipe itself, given that its body expands when heated.
Pipes should be fastened to the boards with clamps. But before laying them, it is necessary to lay out a vapor and waterproofing material, and lay thermal insulation on top of it.
So that during the repair of the heating system it is not necessary to open the floor, fittings and connecting fittings should not be under it. Installation should be carried out in such a way that all fasteners, valves and other fittings are above the floor covering.
In the photo: Radiation system and underfloor heating
Expert recommendations: 10 tips for those who decide to install a radiant heating system themselves
Heating experts recommend listening to the following tips:
- During installation, temperature controllers and thermostats should be installed at some distance from heat sources so that their readings are not distorted;
- Before starting the installation of the circulation pump, it is recommended to flush the system so that there are no solid impurities left in it that adversely affect the rotor and impeller;
- If it is assumed that the pump will be installed on a branch with hot water, then when buying a unit, you should pay attention to the temperature regime of operation. A pump that is not designed to work with hot temperatures is installed in the return;
- It is advisable to mount an air vent with the pump.
- Before the control and subsequent starts of the pump, the system must be filled with water. The device must not be switched on dry.
- It is advisable to cover the draft floor, on which the pipelines of the beam system are laid out, with a heat-insulating film, and put on corrugated sleeves on the pipes. To make it easier to distinguish between supply and return pipes, two-color hoses should be chosen. For heating, manufacturers produce red and blue. They shouldn’t be tight. There should be a free space of 2-3 mm between the sleeve and the pipe, since hot pipes expand from heat.
- If the house, even private, is built on two floors or it simply has an attic, a separate collector is installed on each floor. At the same time, the riser is located in the corner closest to the location of the collectors. In multi-storey buildings, for ease of installation, collectors are usually located one above the other and each, respectively, on its own floor.
- According to some experts, there is no need to install pressure gauges or thermometers on the manifold. Thermostats are placed in a heated room, they are available on the boilers and the meter. By the way, the main indications are taken from the latter. Manifold gauges are an unnecessary luxury.
- In stone and, especially, in panel houses, heating will be economical and sufficiently effective if the outer walls and floor are first insulated.
- You should not save on steel fittings connecting the radiator to the underfloor heating. The tube of L-shaped products is stronger than heating pipes, so it will eliminate breakage in the connection.
“I heard from specialists that the beam is an indestructible system, but somehow I didn’t really believe it until I installed it myself in my house. I planned it myself, and, to be honest, without really going into calculations and engineering subtleties.
But just in case, a control valve was installed on each battery. Adjusted once on first start. Batteries heat up evenly. I haven’t made any further adjustments, and probably won’t. The system is simple and reliable. She is repairable. Each battery, if necessary, can be repaired without shutting down the entire system. Which is also a very big plus for beams.”
The advantages of beam mounting, in my opinion, include:
- comparative simplicity of design;
- accuracy in balancing, in other words, in setting up equipment;
- smaller, in comparison with other schemes, the number of connected elements.
Well, and of course, the ability to measure, control each beam separately, and also turn them off at one point. The latter outweighs all the advantages and even disadvantages.
The disadvantage of the system is the impossibility of open installation. Everything is hidden in the floors or in the niches of the wall. This, of course, is beautiful, aesthetically pleasing, but not always convenient. And another drawback of the system is its overpriced price. Although pipes and fittings are used more, but due to their smaller diameter, their price is cheaper, which partly compensates for the increased consumption of materials. For example, if pipes and fittings of 20-25 mm are used in a tee wiring, then in the radiant heating scheme their size is 15-20 mm.