Electric radiant floor with their hands

The material in this article is designed for real men, those who not only love the comfort, but also used to create his own hands, believing that no, even the most skilled specialist does it better than those who do not just know how to handle the tool and does something for yourself. The following will be discussed on the establishment electric underfloor in concrete screed. So, it is necessary to arrange a warm floor, and how to do it.

Considering that, although the article and is intended for those who have the tool does not fall out of the hands, yet However, for many of them this is the case it may be a completely new and so, for a start, a bit theory.

Selection of heating cable

For underfloor produced two-solid or heating cable. Core cable is designed for heating in places where the current connection with its two opposite ends is difficult, for example, for heating pipes or gutters. Core cable has a high cost, which makes it uneconomical to use for home heating.

general power heating cable

It must be equal to the floor area, under which it will be multiplied by the specific heat capacity W / m2. It is necessary to consider that on the floor, in those locations where it is laid under the cable must not be furnished or devices with low or unventilated gap therebetween and a floor, e.g., refrigerators, cabinets without legs, showers booths. When the heating cable is not used for general space heating, but only to give the floor comfortable temperature, it is best to place it only in those places under the floor, where it will be possible walk. This will not only simplify installation but also save on electricity.

The heating cable must be purchased with some reserve power. We should not fear that it will lead to overuse of electricity. The fact is that in any case, the cable is calculated with a certain margin, calculated on the severe frosts, when the temperature drops below - 20º C. The low-power cable can not cope with heating, in such weather. Powerful heating cable at moderate chills, and in the offseason, will simply be more likely to turn off thermostat.

Another positive factor that the cable is chosen with a margin of power is that it allows you not to puzzle over complex enough electrical calculations. To select a specific heating capacity should be taken into account two points - the maximum allowed for any type flooring specific power cable and the magnitude of this power recommended for various conditions of use floor heating.

Reserve specific power cable for different types of floor covering:

• Natural cork - not more than 80 W / m2;
• Laminated flooring - no more than 120 W / m2;
• Natural parquet - no more than 150 W / m2.

Choice of cable power depending on the usage conditions of a warm floor:

• Minimum display (Heated floor is a secondary source of heat), while the coating made of a natural parquet, laminate material, natural cork - 80 W / m2;
• Minimum display, when coating of a ceramic tile or decorative stone - 100 W / m2;
• Heating well insulated space according to the norms of DBN V.2.6-31 2006 - 150 W / m2;
• Heating medium warmed or volumetric premises with high ceilings and large windows - 200 W / m2.

For example, to implement the minimum required heating lined with decorative stone floor area 8 m2 (minus the area occupied by furniture), indoor, having the main heating source, obtain the value of the required power of 8 * 100 = 800 W, which means that it is possible to select a cable having a maximum value close to it power.

choice of thermostat

The thermostat is needed to continuously maintain a comfortable temperature in the heated space saving and electricity, which is achieved by the fact that it turns off the electric cable, when the air temperature in the room above installed.

Distinguish between ordinary and sophisticated thermostats for underfloor heating. Conventional removed only readings of air temperature inside the room, and sophisticated thermostats are equipped with an additional sensor, which allows them to take into account the outside temperature. This is necessary to enable or disable the sensor Heated floor not after the room has to be cold or warm, and considering the time required for heating or cooling of the floor heating. In terms of a complex probe has no special advantages of electricity-saving, but it significantly increases the level of comfort. Use of a complex temperature control is particularly advantageous with floor heating apparatus on the thick heat-storage screeds (5 cm). The simplest model of programmable thermostats cost about $ 50 and pay off within two or three years of operation.

Choosing thermostat, should take into account its maximum power handling, which should exceed the maximum cable capacity. Cheap thermostats designed to work with the devices, power to 2 kW.

Installation of floor heating cable

Installation of electrical floor heating system starts with marking the area on which the calculation will be laid cable laying step.

For calculation step of laying of the heating cable must know the length and the surface to be heated. For example, if the heating area is 20 m2, and the cable length - 140 meters, the stacking step is 20/140 = 0.14 m, or 14 centimeters. cable laying step may be rounded to 1-1.5 centimeters. For example, for the convenience of mounting a mounting tape, the calculated 14 centimeters to 15 can be rounded. You need to know that the smaller the step of laying, the more uniform will be warmed floor. For this reason, you should choose the best possible long cable (with the same capacity). Uniform heating can be achieved using dense (crushed stone) and thick (5 cm) screed.

A few simple rules that must be adhered to during installation:

• Land cable to avoid overheating must not cross the hot water pipe and overlap one another;
• Step laying should be more than 7 centimeters, a smaller pitch helps to overheating;
• The bending radius should be less than 40 mm, since this may result in damage to the cable failure;
• On the floor, in places where cable is laid, should not be sanitary, household appliances and furniture, with the exception of furniture on high legs (15 cm and above).

Tape for installation of the heating cable

Cable Installation based on the most convenient assembly perforated zinc tape, allowing withstand multiple stacking step 2.5 centimeters (10 cm, 12.5 cm, etc.). To the base of the tape is attached by nails or dowels construction with pre-drilling diameter, depending on the base strength. Strips of tape is most conveniently placed at a distance of two feet from each other.

When used in floor heating devices insulation (Styrofoam), the cable must not be laid directly on the foam, which can lead to overheating. In this case, must be used for mounting a grid of steel wire with a diameter of 4 mm, having a cell 10x10 centimeters. Cable conveniently attaches directly to a steel grid, using special plastic clips.

Mounting thermostat and temperature sensors

The thermostat is mounted on the wall near where the cable is connected to the network. When installing the thermostat should be noted that to it should be easily accessible. When installing the thermostat for floor heating bathroom or other sanitary facilities (bath, sauna, etc.) the thermostat should be installed on the outside of the premises, in order to avoid breakage from excessive humidity. The exact connection diagram of the device is available in the installation instructions that are supplied every thermostat.

Sensors thermostat set so that they can be easily replaced in case of breakage. To do this, they are placed in the mounting tube, usually supplied thermostat. Sensors are placed at one end of the tube and its second end is insulated by means of insulating tape, adhesive tape or adhesive compositions. A tube with an internal temperature sensor located in close proximity to the floor surface midway between the cables. If its diameter is less than the height of the screed, for example, when the warm floor is laid under the tile glue - it is necessary to arrange the recess under the sensor. outdoor air temperature sensor (if present) is located on the outside of the room outside, so that it has no contact with heated surfaces.

Electrical connection

Heated floor connecting to the network must be satisfied that the wiring corresponds to a load from the current intensity. The maximum load depends on the material and cross-section of the cable wires:

Table. Wire cross-section, depending on the maximum load

The cross section provodaPredelny current, A

For copper cables

For aluminum kabelya2h1,518-2h2,525192h4,03225

Compound wiring harness

Underfloor heating is a system of high power, consumes more current, so you should pay special attention to the connection of wires during installation. Poor quality of connections can lead to increased heating in areas of poor contact and subsequent rapid oxidation wires that worsen even more electrical contact - is formed vicious circle. All this can lead to electrical fires. When connecting contact wires by twisting almost always worsens gradually, particularly when twisting wires made of different materials (copper, aluminum). The latter, in fact, generally not allowed.

To connect the pins is best to use spring terminals made by Cage Clamp technology. They allow you to safely and easily connect both single-core and multi-core copper and aluminum conductors up to 4 mm2. Picking up the terminal for installation, should be considered the maximum load current.

screed

Before pouring the concrete solution, clean the surface of the floor of debris, dirt and dust, the solution does not peel off after solidification warping. At the device on the old ties insecure grounds recommended hardening primers. Under the cable must not be sharp protruding objects that could damage it.

When the device thin floor heating (or under the ceramic tile) For filling the heating cable can be used tile adhesive.

it is recommended to use the following composition (parts by volume) to prepare a cement-sand mortar screeds for thick:

• Cement PC-400 - 1 part;
• Sand - 4 parts;
• Crushed fine - 5 parts;
• Water - 0.6;
• The plasticizer (e.g., C-3) - 1% by weight of cement.

Of great importance is the amount of water than it is, the stronger and more likely shrinkage cracking. Formulations without plasticizers is undesirable to use for the same reason. Lack of gravel in the composition also increases the likelihood of cracking. It is recommended to use self-leveling mortars.

The use of lightweight aggregate (expanded clay, perlite) to a concrete screed floor heating is not allowed. This would lead to a violation of heat and contribute to overheating of the electric cable. To avoid the formation of local hot spots is necessary when pouring the solution was carefully ram, so that no cavities around the cable.

After pouring the solution to prevent rapid drying screed must be covered with plastic wrap. At room temperature the screed must be maintained to turn on the system at least 28 days.