Mixing knots. Mixing unit: selection, installation, operation

The use of such structural elements as mixing units in "warm floor" systems, as well as ventilation equipment, allows to regulate the temperature of air or water entering the room. When installing them, you must follow certain rules.

Why you need a mixing unit for a warm floor

This kind of equipment is used to adjust the temperature of the coolant mainly in private homes. "Warm floors" are usually connected to the boiler. And consequently, the water in the pipes laid under the screed, and the water intended for domestic needs, have the same temperature. And this, of course, is not always convenient, especially in the summer. Hot water is needed and at this time, but the heated surface of the overlap will clearly be superfluous. In addition, in the absence of a mixing unit, the floors can be too hot even in winter.

What is a mixing unit

These components of the "warm floor" systems consist of the following elements:

• Circulating pump,
• A control valve or a valve,
• Check valve ,
• Ball valves,
• Balancing valve,
• Filter,
• Temperature sensor.

Principle of operation

Usually this element of the heating system "warm floor" is put on the supply pipe. In the event that the water temperature exceeds the specified values, the valve will open and the already cooled coolant from the return flow will begin to flow into the pipeline. As a result of mixing, the temperature of the water in the supply pipe will decrease.

For small houses, only one mixing unit is usually used. In cottages and two-three-story suburban buildings they are installed a few. Depending on the principle of operation, these elements can be included in the system in parallel or in series.

Cost

Since the self-assembly of this element - the procedure is technically quite complex, experts advise owners of country houses to buy a ready-made mixing unit. The price for it, depending on the brand, the degree of equipment and performance, can fluctuate around 7-15 thousand rubles.

How to choose

First of all, when choosing this equipment, you should look at the manufacturer's brand. Most likely, it will work very well, for example, the Smex mixing unit, which includes ARA 659 servo drives. The latter are designed for proportional control of the coolant temperature.

Another popular brand are the Valtec nodes. Their main advantage is the ability to manually adjust the heating of floors.

This equipment is also selected depending on which boiler is used in the system, as well as on what is actually developed, the scheme of the warm floor itself. When buying, you should first look at the permissible water temperature, maximum and operating pressure, and the pump head, which should be equal to six meters.

How to install

In private houses, mixing units with a two-way valve are usually used. Such equipment is installed in the following order:

• On the wall opposite the pipe clamps are fixed.
• The unit is connected simultaneously to the pressure and return pipes (via tees with thermometers and a ball valve), and also to the wall.
• The tees are connected bypass.
• A pressure circulating pump is connected to the bypass .
• The ball valve on the supply line is connected to a short tube-tee and a flowmeter.
• At the end of the latter is installed a blind valve.
• Lower valve also with a tee, closed valve.
• If necessary, automated drives are connected.
• Taps are connected with the outlets of all heating circuits.
• The knot node is adjusted.

Of course, the installation of equipment will be faster if the scheme of the warm floor is drawn before the installation begins. The located node can be at any convenient point in the system. But it is better to slash it where there is less chance of air bubbles entering the coolant. Also, make sure that the water does not get on the part of the unit that is under tension.

Rules of operation

When using the "underfloor heating system" assembly, the manufacturer's recommendations in the instruction manual should be followed first. The temperature and water pressure should not exceed the operating parameters, and in extreme cases - the maximum permissible.

The use of mixing units, even equipped with filters, increases the requirements for the quality of the coolant. Water should not contain solid impurities. It is highly undesirable that chemically aggressive substances are also present. The design of the unit may include vulnerable parts of copper, plastic, zinc or rubber.

Mixing unit of air-conditioning unit

Constructions of this type are used in systems equipped with water heat exchangers. Their main purpose is to maintain the temperature of the air entering the room at the level set by the owners.

Mixing units of this type operate in the same way as elements that are mounted in the "warm floor" system. The difference is that in this case three-way valves are usually used . The assembly is as follows:

• A filter is installed on the return pipe of the heat exchanger.
• Then the circulation pump is connected.
• An electrically-actuated valve is mounted.
• The valve is connected to the supply line bypass.
• On the return and supply pipe are installed ball valves and are connected bypass. On the latter, a non-return valve and a control valve are installed in series.
• An automatic airflow cuts into the supply line.
• Both the supply and return pipes are equipped with service cranes.

As you can see, it is quite difficult to mount the mixing unit of the air-handling unit. Therefore, it is better to entrust this work to specialists. If errors are made during the assembly, the ventilation system may not work properly.

The ventilation mixing units are also operated according to the recommendations of the manufacturer of this particular model. Monitor the quality of the coolant is important in this case.