Collector for underfloor heating

Many of us today are trying to give preference to the most convenient, practical and efficient heating systems. Traditional heating of residential premises with the help of radiators today no longer meets the increased operational requirements that are imposed on heating systems. Today it is possible to compare, not only in theory, the technological capabilities of warm water floors with the operation of radiators, but also to be convinced in the practical plane of the effectiveness of this method of heating. Due to the design features, great opportunities are assigned to the warm floor.

Proper installation and connection of all elements of the heating system will allow your desires to come true. One of the main structural elements, without which the operation of the heating system will not be effective, is the floor heating collector.

The value of the collector for the heating system

The technological capabilities of the warm floor allow it to be used as a full-fledged heating system for heating the entire residential facility or as an auxiliary option. Today, small, technologically limited, projects of underfloor heating with the help of a liquid heat carrier are being successfully implemented. Bathrooms, children’s rooms and other small rooms are successfully heated with water pipes laid in the floor.

Connection scheme for underfloor heating without a collector

But in most cases, such heating options are not adjustable. What is the temperature of the water in the central heating batteries or in the DHW system, this intensity will be the heating of the floors in your premises. Large inertia and the lack of fine adjustment are the main disadvantages of underfloor heating, made according to a simplified scheme.

For reference: the optimum temperature of the heat carrier circulating in the water heating circuit of underfloor heating is 35-45⁰C. In a centralized system and in the DHW main, the water is hotter, so an unregulated floor in this situation will be ineffective.

The problem can be solved by installing a mixing unit, connecting a floor heating collector along with other necessary equipment. For a bathroom, when using the type of connection «riser-water circuit», the installation of such a complex unit is not cost-effective and impractical. However, when using the underfloor heating system on a large scale, the collector will become a convenient adjustment and safety tool.

Autonomous heating systems of residential facilities, the task of which is to heat the floor covering in residential premises, must be equipped with a special preparatory station. The composition of the mixing unit includes a manifold and a pump, equipment without which your underfloor heating will become a «graveyard of consumables.»

Wiring diagram for equipment without circulating pump

For a warm water floor, where the main work is done by heated water circulating in the pipeline, an important point of functionality is the distribution of water flows. Thanks to the design of the distribution unit, the required water temperature in the water circuit, the optimal intensity of the water flow, is achieved. With the help of a collector, it is possible to set the necessary temperature conditions in residential premises, to carry out safe switching on and off of the system.

Device design

If the collector is evaluated simply visually, then at first glance it is a whole group of pipelines assembled in a certain order. In its appearance, the device resembles a comb, for which it received its second unofficial name. The task that this node performs is to mix the various streams of water. As a result, a single coolant flow of the required temperature and intensity is obtained at the outlet. For underfloor heating, this condition is mandatory, otherwise the meaning of the operation of a heating system of this type is lost.

Depending on the collector design, three types of liquid medium mixing are used in practice:

• sequential mixing;
• parallel;
• combined type of mixing.

On a note: most often in the conditions of operation of warm floors at the household level, sequential mixing is used, as a result of which all the water circulating in the heating system from the heater to the heating pipes is used for its intended purpose.

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The figure-scheme shows two options for the operation of the mixing unit.

The sequential type of mixing involves the pumping of mixed water from the heating source into the water floor loop in one direction. Parallel type of mixing, both heat carrier lines, main and return are separated. In this case, a significant part of the thermal energy is lost. For parallel types, uneven supply of coolant is characteristic.

On a note: only equipping the mixing unit with a two-way valve will allow you to achieve the ability to adjust the flow rate and heat the water in the heating pipe.

Combined type using both series and parallel mixing type. Such collector schemes are less common due to the features and complexity of the design.

The principle of operation of the device explains the completeness of the collector group. It includes:

• three-way valves (regulating, mixing and mixing), which is installed on each inlet and outlet of the manifold;
• pipeline with tees;
• circulation pump;
• adjustment and automation group.

Installing a collector for your underfloor heating makes the entire heating system complete and functional. The pump drives water into the heating circuit until the temperature of the heating medium reaches the specified parameters. The operation of automation begins from the moment when it is necessary to shut off the flow of hot water to enter the heating pipe. All standard collector models are equipped with air vents and a drain system, a valve through which water is drained from the system.

The principle of operation of the collector

The operation of the «warm floor» heating system depends directly on the setting of the collector, which is a switchgear. Let’s see what it looks like:

— boiler water coming from an autonomous boiler or through the riser of the central heating system has a temperature of 50-70⁰C, enters the manifold through a zone valve equipped with a thermostatic head.

• then water, if its temperature is higher than the optimal parameters, is mixed with the return, after which it enters the collector, which distributes water of the desired temperature through the water circuit loops.
• when the coolant reaches the optimum temperature parameters, the zone valve closes the flow direction, directing water to the return supply system.

Thanks to such a system, a warm floor can work for a long time without the participation of a heat carrier heating source.

When the water temperature in the underfloor heating system drops, the reverse circuit is activated.

• the zone valve opens access to water, as a result of which the mixing of water with the flow circulating in the return begins. The temperature of the heat carrier in the heating circuits rises again to the desired values.

It is possible to achieve the accuracy of setting the water flow in the underfloor heating pipeline by adjusting the flow meter. The parameters are set within 1-1 l / min. in accordance with existing thermal calculations.

Mixing valves work to eliminate linear expansion and provide control over the flow of coolant in water circuits.

Usually collectors with two outlets are used, however, there are cases when it becomes necessary to install a mixing unit with 4-6-8 and 12 outlets. In order to hide such a massive and unsightly structure in living quarters, a manifold cabinet for underfloor heating is designed.

In order to achieve a uniform distribution of the water flow through the water pipes, the return inlets are equipped with servo drives that interact with temperature sensors and automatically shut off the water supply to the heating floor pipeline. Almost every model of the mixing unit is equipped with an electronic dissipation circuit. It controls the operation of the circulation pump and the safety thermostat.

On a note: the presence of such equipment is due to the fact that warm floors are low-temperature heating systems. Electronics allows using a pump to regulate the heating temperature of the coolant, eliminating overheating of the heated room and thereby eliminating discomfort inside the room.

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Model selection

In most cases, the choice of collector model depends on the size of the heated room and the requirements for the heating system. Where and how a warm floor will be built, the level of safety become decisive factors when choosing equipment. The mixing unit is the most vulnerable element of the device. In view of the fact that both cold and hot water circulate simultaneously in this part of the structure, it is important to ensure the safety of this block from mechanical damage.

Many of us are wondering how to assemble a collector for a warm floor if the device has such a complex structure and design. The answer is simple. The complexity is only visible. With a detailed study of all the details and structural elements, understanding the goals and objectives of each device, you can independently assemble and connect the collector to your heating system. The selected materials, build quality are a guarantee that your underfloor heating will work properly.

In order to act correctly, let’s dwell on the details that should be considered when buying a collector. The best option is a model whose case is made of brass or stainless steel. In both options, the choice will be correct, the only condition is the different price of such devices.

In terms of functionality, both simple and complex types of mixing units are on sale. In simple collectors, there is a minimum set of devices that ensure the operation of a warm floor in narrow parameters. For complex structures, it is typical to equip with additional devices and sensors.

For example: not all models are equipped with a safety device, Mayevsky crane, drain valves and flow meters.

The price issue in this case should not be an obstacle for you when choosing equipment. A collector equipped with an automatic thermostat will become a real assistant for you, who will do all the hard work for you. Thanks to automation, the system itself will control the working conditions, adjusting the flow rate as necessary, and finally drain the water from the pipeline.

The standard collector model comes with thermometers, thanks to which either you or the automation can minimize heat loss.

If there are several large rooms heated by underfloor heating, it is recommended to install not one, but two collectors.

On a note: the length of the heating pipe of one circuit should not exceed 120 meters. To work with several water circuits in one room, mixing units are taken for several inputs.

Conclusion

Installation of a warm floor, i.e. laying a warm floor is only part of a long and big job of equipping a home heating system. After you lay the water pipes in the floor under a concrete screed or under a stacked structure, the connection is the most important step.

Properly made preliminary calculations of underfloor heating will allow you not only to choose the required collector model, but also to get an idea of ​​how the water circuit will be connected to the heating system. Following the necessary instructions and guided by the advice of professionals, connect each pipe to the required socket. It is important not to confuse the connection points. Main feed inlet with return inlet. For ease of connection, there is a marking of the inputs: the supply pipe is indicated in red. In blue, the inputs for the reverse flow are indicated. Connection of pipes to the inlets is carried out using fittings.

You can check the correctness of the connection during the control, first start. In the absence of visible flaws in the functionality of the mixing unit and the normal operation of the underfloor heating, you can proceed to the final work.