Mixing knot with own hands. Pump-mixing unit: principle of operation

The so-called warm floors perfectly proved themselves as a system for heating private houses. It is often possible to find dwellings in which only a few rooms are heated in this way. But increasing popularity is gaining the tendency to heat the whole house with warm floors. Also you can find combined heating options - warm floors and conventional radiators.

The heating system, which supplies warm floors, usually has a temperature of about eighty degrees Celsius. For warm floors, this temperature is unacceptable, since it can lead to spoilage of flooring and interior items, and people will be uncomfortable in such a room. For such systems, a temperature of not more than 40 degrees is selected. Therefore, they also provide a mixing unit Valtec. Below we will consider all the details about it.

Do I need to install such a node?

Let's see how the average heating system is performed. So, it consists of the following elements:

• Heating boiler.
• Heat carrier.
• High-temperature circuit.
• Required number of circuits for warm floors.

As noted above, the boiler heats the heating medium to 80-90 ° C, and the temperature of the floor itself should not exceed a thirty-degree value. Given the height of the screed and the fact that the floor is provided with a floor covering, it turns out that the temperature of the coolant circulating through the pipes can be up to 55 degrees.

Accordingly, this can be achieved by connecting the contour of the warm floor to the external circuit through the pump-mixing unit (Valtec including). It should be added that they are not allowed in the system of warm floors, when the installation does not heat the liquid too hot, and also if the heating system is built without using circuits with a high temperature.

How the pump-mixing unit works for warm floors

Let's analyze the principle of operation of this element, designed for systems of warm floors. We omit the process of heating the coolant by the boiler and proceed directly to the stage of interest to us. Heated liquid is selected to the collector of warm floors and due to the presence of a special safety valve it stops in case of too high a temperature. A pressure is formed, which leads to the opening of a damper that allows the cooled liquid from the reverse circuit (meaning a cooled liquid that has passed through the entire contour). The valve closes at a time when the temperature of the water in the collector becomes favorable for the system.

Let us consider in more detail the collector, which provides the optimum temperature in warm floors and maintains the required pressure for circulation of the coolant. Its main parts are:

• The safety valve, which was mentioned above. It is intended for mixing in the case where the water in the collector is unacceptably hot.
• Circulation pump, maintaining the water pressure, creating conditions for uniform heating of the floor.

Also, the collector assembly may have other auxiliary components, such as a bypass (device designed to protect against overloads), various valves and air diversions.

It is absolutely accurate that the mixing unit is installed up to the contour of the warm floors, however, it is not so clear with the installation site. It can be located in the boiler room or directly in a heated room. Mixing units are distinguished by valves that are used in them. The most common are two-way and three-way.

Two-way valve

Such valves are called feeders. The design of this element includes a fluid sensor that checks the coolant supplied. If it becomes necessary, it stops supplying the hot carrier from the unit.

As a result, the mixture is continuously fed with water from the return circuit. When this liquid cools sufficiently, a portion of the hot coolant is added by means of the valve. Based on such information, we can make the assumption that a system with similar valves will never overheat, and the warm floor will serve for a long time. An undoubted advantage is also the smooth adjustment, since the valve has a small capacity.

Many experts choose in favor of two-way valves when installing a mixing unit. However, it should be noted that for their application it is necessary to fulfill one condition - the area of the heated room should not be more than 200 sq. M. M.

Three-way valve

This type of element is different in that at the same time it is both a bypass valve and bypass. Inside the three-way valves, the hot coolant and the liquid from the return circuit are mixed. Also between the feed and the return is a damper. Its position, respectively, regulates the supply of the coolant.

This type of connection is universal, it is applicable for large systems (the scheme of a mixing unit with a large number of circuits). However, there have been no shortcomings here. There are times when the thermostat gives a signal to the valve to open completely, and, accordingly, water is supplied to the collector at a temperature of up to 90 degrees. As noted above, such a temperature, together with sharp jumps, can lead to failure, namely, to the fact that the pipes will burst.

Another drawback is the large bandwidth. This fact can lead to a dramatic change in temperature even with a slight displacement of the valve.

Outdoor temperature sensors

Such devices are necessary in the system for automatic adjustment of the coolant depending on the weather conditions. For example, when the street is cold, a signal is sent to increase the temperature of the coolant, and in case of warming, the sensor tells the system that the floor temperature can be reduced.

The valve design means a 90 degree turn. The special controller divides these 90 degrees into 20 sections and monitors the weather conditions outside the window. If the carrier temperature does not match the weather conditions, the valve rotates by the required number of divisions. Naturally, these manipulations can be done independently, but this is very inconvenient.

Scheme of the mixing unit

Consider the most popular schemes of knot nodes. It should be said that there is a need for thermostats, flow sensors and valves for each of the collectors.

The Valtek pump-mixing unit is designed for a single circuit. The average floor space is 20 square meters. M.

Symbols on the diagram

1. Mixing valve.
2. Nipple 1 to 3 quarters.
3. Circulation pump.
4. Nipple 1-1 / 2 inches.
5. Ball valve ½ in. (Outside / outside).
6. Connector 16-1 / 2 inches.
7. Futorka on 3/4 inches-1/2 inches.
8. A half-inch barrel.
9. Half-inch tee.
10. Ball valve 1/2 in. (Out / out).

Mixing unit Valtek with one circuit and automatic adjustment

Notation:

1. Mixing valve.

2, 16. Futura 1-1 / 2 inches.

3, 8. The tap is ½ inch.

4,7,11,21. Connector 16-1 / 2 inches (male).

5,6,12,22. Metal-plastic pipe.

9. Nipple 1-1 / 2 inches.

10. Tee ½ inches.

13. Thermal head with remote sensor.

14. Nipple 1 inch.

15. Pump nut nuts 1 inch.

17. The elbow is ½ inch.

18. The pump is circulating.

19. Extension piece ½ ", 100 mm.

20. Thermal head sensor.

Mixing unit "Valtek" with auto-adjustment, providing from two to four contours of warm floors. The area of heating - from twenty to sixty square. M.

Specification

1. Remote sensor on the thermal head.

2. Mixing valve.

3. The tap is 3/4 inches.

4. Futurka on 1-3 / 4.

5. Tee 1 inch.

6. Nipple 1 inch.

7. The pump is circulating.

8. Valve tap on collector 1-1 / 2 inches.

9. Cover plate from the outside. Thread 1 inch.

10. Collector complete with cranes 1-1 / 2 inches.

11. Connector for connection of pipe and manifold 16-1 / 2 inches.

12. Metal-plastic pipe.

13. Pump nut nuts.

14. Thermal head sensor.

Let's consider some elements by which the scheme can be supplemented:

• The secondary circuit balancing valve , which allows the adjustment of hot and cold water from the return circuit. The valve is rotated with a hexagon. In order to reliably fix it and prevent displacement, it is installed with a clamping screw. It should be noted that in most cases it has a scale for measuring the flow rate.
• Shut-off valve for the radiator circuit, performing balancing functions. It is necessary to connect the knot unit with other parts of the heating system. To turn it, you also need a hexagon.
• Bypass valve. A kind of fuse that protects the circulation pump in the absence of water passing through it. Its operation occurs after the pressure in the system has been reduced to a certain value.

Let's consider, as the scheme of connection of mixing units

It should be noted that the schemes differ by the principle of the heating system, there are single-tube and with two pipes. Suppose there is a single-pipe system, in which case the bypass device must be permanently open. This is necessary in order for some amount of hot coolant to be able to approach the radiators. If there is a two-pipe system, the bypass device will be permanently closed, since there is no need to operate it.

A small note: the collector group does not have to be placed up to the contour with radiators. After all, if we consider that a heated house of small dimensions, the temperature of the coolant will not be able to drop during the movement through the pipes. Therefore, the collector assembly can also be installed in the opposite direction from the radiator circuit.

Finished node cost

Naturally, you can not torture yourself by collecting a mixing knot with your own hands, and purchase a finished product. After all, such a task will require careful study of various schemes of work. Ready-made knots can be easily found in building stores, for example the Combimix mixing unit from Valtec. However, we must prepare for the fact that the price tag is unlikely to please the buyer. Although this price is justified: the purchase of a ready-made node will help to save the consumer from errors in calculations, assembly and installation.

Say a few words about the most popular in Russia manufacturer of mixing units - the Italian company Valtec. A kit consisting of a mixing unit and a pump will cost about fifteen thousand rubles. The analogue from the manufacturer Watts Isotherm will cost about the same money. Those who are not afraid of difficulties and who have free time can try to assemble the mixing knot with their own hands from different parts.

Conclusion

After the entire assembly works have been completed, it is necessary to connect the mixing unit to the contours. Excellent assistants in this case will be special fittings and adapters. And it is very important to perform system balancing before the first start.

So, we found out how the mixing unit is installed and what this element is. Note that there are such elements of the order of 13-16 thousand rubles.