The so-called warm floors have proven themselves as a system for heating private homes. You can often find homes in which only a few rooms are heated in this way. But the tendency to heat the whole house with underfloor heating is gaining more and more popularity. You can also find combined heating options - warm floors and familiar radiators.
A heating system that supplies underfloor heating usually has a temperature of about eighty degrees Celsius. For warm floors, this temperature is unacceptable, since it can lead to damage to the flooring and interior items, and people will not be comfortable in such a room. For such systems, a temperature of no higher 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 made. So, it consists of the following elements:
- Heating boiler.
- Coolant.
- High temperature circuit.
- The required number of contours for underfloor heating.
As noted above, the boiler heats the coolant to 80-90 ° C, and the temperature of the floor itself should not exceed thirty degrees. 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 floor heating circuit to the external circuit through the pump-mixing unit (including Valtec). It is worth adding that their absence in the system of underfloor heating is allowed, when the installation does not heat the liquid too hot, and also if the heating system is built without the use of high temperature circuits.
How does the pump and mixing unit for warm floors
We will analyze the principle of operation of this element, designed for underfloor heating systems. We omit the process of heating the coolant with the boiler and proceed immediately to the stage of interest to us. Heated liquid is drawn to the collector of underfloor heating and, due to the presence of a special safety valve, stops in case of too high a temperature. Pressure forms, causing the damper to open, letting in the cooled liquid from the return circuit (meaning the cooled liquid that has passed through the entire circuit). The valve closes at the moment when the temperature of the water in the manifold becomes favorable for the system.
Let us consider in more detail a collector that provides optimal temperature in warm floors and maintains the required pressure for circulation of the coolant. Its main parts:
- The safety valve mentioned above. It is intended for mixing when the water in the collector is unacceptably hot.
- A circulation pump that maintains water pressure, creating conditions for uniform floor heating.
Also, the collector assembly may have other auxiliary components, such as a bypass (a device designed to protect against overloads), various valves and air vents.
It is absolutely accurate that the mixing unit is installed up to the contour of the underfloor heating; however, it is not so simple with the installation site. It can be located both in the boiler room and directly in the heated room. The mixing units are distinguished by the valves that are used in them. The most common are two-way and three-way.
Two way valve
Such valves are called supply valves. The design of such an element includes a fluid sensor that checks the supplied coolant. If necessary, it stops the supply of hot media from the unit.
As a result, water from the return circuit is constantly supplied to the mixture. When this liquid cools sufficiently, a portion of hot heat transfer agent is added with the help of the valve. Based on such information, it can be assumed that a system with such valves will never overheat, and a warm floor will last a long time. An undoubted advantage is also the smooth adjustment, as the valve is characterized by a small capacity.
Many experts opt for two-way valves when installing the mixing unit. However, it is worth noting that for their application it is necessary to fulfill one condition - the area of the heated room should not be more than 200 square meters. m
Three way valve
This type of element is distinguished by the fact that at the same time it is a bypass valve and a bypass. Inside the three-way valves, the hot coolant and the liquid from the return circuit are mixed. There is also a shutter between the feed and the return. Its position, respectively, regulates the flow of coolant.
This type of connection is universal, it is applicable for large systems (mixing unit circuit with a large number of circuits). However, there were some shortcomings. There are cases when the thermostat gives a signal to the valve to open completely, and, accordingly, water is supplied to the collector with a temperature of up to 90 degrees. As noted above, such a temperature, together with sharp jumps, can lead to breakage, namely, that the pipes burst.
Another drawback is the large bandwidth. This fact can lead to a sharp 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 weather conditions. For example, when it gets colder on the street, 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 design of the valve involves a rotation of 90 degrees. A special controller divides these 90 degrees into 20 sections and monitors the weather outside the window. If the temperature of the medium does not correspond to weather conditions, then the valve turns by the required number of divisions. Naturally, these manipulations can be performed independently, but this is very inconvenient.
Mixing unit diagram
Consider the most popular mix node patterns. It should be said that there is a need for thermostats, flow sensors and valves for each of the collectors.
Valtek pump and mixing unit is designed for one circuit. The average floor area of 20 square meters. m
Designations on the scheme
- Mixing valve.
- Nipple 1 to three quarters.
- Circulation pump.
- Nipple 1-1 / 2 inches.
- Ball valve ½ inch (in / out).
- Connector 16-1 / 2 inches.
- 3/4 inch 1/2 1/2 inch
- Half inch barrel.
- Half inch tee.
- Ball valve 1/2 inch (bunk / out.).
Valtek single-loop mixing unit with automatic adjustment
Designations:
1. The mixing valve.
2, 16. Foot 1-1 / 2 inches.
3, 8. Tap ½ inch.
4,7,11,21. Connector 16-1 / 2 inches (nar.).
5,6,12,22. The pipe is metal-plastic.
9. Nipple 1-1 / 2 inches.
10. Tee ½ inch.
13. Thermal head with remote sensor.
14. Nipple 1 inch.
15. Union nuts pump 1 inch.
17. Elbow ½ inch.
18. The circulation pump.
19. Extension ½ inch, 100 mm.
20. Thermal head sensor.
Node mixing "Valtek" with automatic adjustment, providing for from two to four contours of underfloor heating. The heating area is from twenty to sixty square meters. m
Specification
1. Remote sensor on the thermal head.
2. The mixing valve.
3. The crane is 3/4 inch.
4. Futorka for 1-3 / 4.
5. Tee 1 inch.
6. Nipple 1 inch.
7. The circulation pump.
8. The valve on the collector 1-1 / 2 inches.
9. End cap 1 inch thread
10. The collector complete with cranes 1-1 / 2 inches.
11. Connector for connecting the pipe and manifold 16-1 / 2 inches.
12. The pipe is metal-plastic.
13. Pump union nuts.
14. Thermal head sensor.
Let's consider some elements with which the circuit can be supplemented:
- Secondary circuit balancing valve for adjusting hot and cold water from the return circuit. The valve rotates using a hexagon. In order to securely fix it and prevent displacement, it is installed with a clamping screw. It is worth noting that in most cases it has a scale for measuring bandwidth consumption.
- Shut-off valve for the radiator circuit, performing balancing functions. It is necessary for the connection of the mixing unit with other parts of the heating system. To turn it, a hexagon is also needed.
- 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 drops to a certain value.
Let's look at the connection diagram of the mixing units
It should be noted that the schemes differ in accordance with the principle of the heating system, there are single-pipe and with two pipes. Suppose there is a one-pipe system, in which case the bypass device must be constantly open. This is necessary so that a certain amount of hot coolant has the opportunity to approach the radiators. If there is a two-pipe system, then the bypass device will be constantly in the closed state, since there is no need for its operation.
A short note: the collector group does not have to be located before the circuit with radiators. After all, if we consider that the heated house is small in size, then the temperature of the coolant will not have time to drop during movement through the pipes. Therefore, the collector assembly can also be installed in the opposite direction from the radiator circuit.
The cost of the finished site
Naturally, you can not suffer, collecting the mixing unit with your own hands, and purchase a finished product. After all, such a task will require a thorough study of various schemes of work. Finished units can be found without problems in construction 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 such a price is justified: the purchase of a finished unit will help to protect the consumer from errors in calculations, assembly and installation.
Let's say a few words about the most popular manufacturer of mixing units in Russia - the Italian company Valtec. A kit consisting of a mixing unit and a pump will cost about fifteen thousand rubles. The American counterpart 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 unit with their own hands from different parts.
Conclusion
After the whole complex of installation works is completed, it is necessary to connect the mixing unit to the contours. In this case, special fittings and adapters will be excellent helpers. And it is very important to balance the system before the first launch.
So, we found out how to install the mixing unit and what is this element. Note that such elements cost about 13-16 thousand rubles.