The use of such structural elements as mixing units in "warm floor" systems, as well as ventilation equipment, allows you to control the temperature of the air or water entering the room. When installing them, certain rules must be observed.
Why do we need a mixing unit for underfloor heating
This type 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 also needed at this time, but the heated floor surface will obviously be superfluous. In addition, without 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,
- control valve or valve,
- check valve,
- ball valves,
- balancing valve,
- filter,
- temperature sensor.
Working principle
Usually this element of the "warm floor" heating system is placed 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 will begin to flow into the line. As a result of mixing, the temperature of the water in the supply pipe will decrease.
For small houses, usually only one mixing unit is used. In cottages and two-three-story country buildings, several of them are installed. 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 is a technically rather complicated procedure, experts advise owners of country houses to buy a ready-made mixing unit. The price for it, depending on the brand, 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 brand of the manufacturer. Most likely, it will work very well, for example, the Smex mixing unit, which is equipped with ARA 659 servo drives. The latter are designed to proportionally control the temperature of the coolant.
V altec nodes are another popular brand. Their main advantage is the possibilitymanual adjustment of floor heating.
This equipment is also selected depending on which boiler is used in the system, as well as on which, in fact, the underfloor heating scheme itself is developed. When buying, you need to look first of all at the allowable water temperature, maximum and operating pressure, as well as the pump pressure, which should be equal to six meters.
How to install
In private homes, mixing units with a two-way valve are usually used. Such equipment is installed in the following order:
- Clamps are fixed on the wall opposite the pipe.
- The assembly is connected simultaneously to the pressure and return pipes (through tees with thermometers and a ball valve), as well as to the wall.
- Tees are connected bypass.
- The pressure circulation pump is connected to the bypass.
- The ball valve on the flow line is connected to a short tee pipe and a flow meter.
- A plug valve is installed at the end of the latter.
- Bottom valve also with tee, closed valve.
- Automated drives are connected if necessary.
- The tees are connected to the taps of all heating circuits.
- The submix node is configured.
Of course, the installation of equipment will be faster if a warm floor diagram is drawn before installation. The node can be located at any convenient point in the system. Butit is still better to embed it where there is a lower probability of air bubbles entering the coolant. You also need to ensure that no water gets on the parts of the assembly that are energized.
Operating Rules
When using the node of the "warm floor" system, first of all, you should follow the manufacturer's recommendations set out in the instructions. The water temperature and pressure must not exceed operating parameters, and in extreme cases - the maximum allowable.
The use of mixing units, even those 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 in it. The design of the assembly may include vulnerable parts made of copper, plastic, zinc or rubber.
Mixing unit for air handling unit
Designs 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 work in the same way as the elements mounted in the "warm floor" systems. The difference is that in this case three-way valves are usually used. Assembly is done like this:
- A filter is installed on the return pipe of the heat exchanger.
- Next, the circulation pump is connected.
- The motorized valve is mounted.
- The valve connects withsupply line bypass.
- Ball valves are installed on the return and supply pipes and connected by a bypass. On the latter, a check valve and a control valve are mounted in series.
- An automatic air vent cuts into the supply line.
- Service taps are installed on both the supply and return pipes.
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 process, the ventilation system may not work properly.
Mixing ventilation units are also operated according to the recommendations of the manufacturer of this particular model. It is also important to monitor the quality of the coolant in this case.
