Water heated floors contour length. Underfloor heating design: general recommendations

Topics covered here include: maximum length contours of a water heated floor, the location of pipes, optimal calculations, as well as the number of circuits with one pump and whether two are the same.

Calls to measure seven times folk wisdom. And you can't argue with that.

In practice, to embody what has repeatedly scrolled in the head is not easy.

In this article we will talk about the work related to the communications of a warm water floor, in particular, we will pay attention to the length of its contour.

If we are planning to install a water heated floor, the length of the circuit is one of the first issues that needs to be dealt with.

Pipe arrangement

The underfloor heating system includes a considerable list of elements. We are interested in tubes. It is their length that determines the concept of "the maximum length of a warm water floor." It is necessary to lay them taking into account the characteristics of the room.

Based on this, we get four options, known as:

snake;
double snake;
corner snake;
snail.

If done correct styling, then each of the listed types will be effective for space heating. Different can be (and most likely will be) the footage of the pipe and the volume of water. The maximum length of the water-heated floor circuit for a particular room will depend on this.

Main calculations: water volume and pipeline length

There are no tricks here, on the contrary - everything is very simple. For example, we chose the snake option. We will use a number of indicators, among which is the length of the contour of a water-heated floor. Another parameter is the diameter. Mostly pipes with a diameter of 2 cm are used.

We also take into account the distance from the pipes to the wall. Here it is recommended to fit in the range of 20-30 cm, but it is better to place the pipes clearly at a distance of 20 cm.

The distance between the pipes themselves is 30 cm. The width of the pipe itself is 3 cm. In practice, we get a distance between them of 27 cm.
Now let's move on to the area of the room.

This indicator will be decisive for such a parameter of a warm water floor as the length of the circuit:

Let's say our room is 5 meters long and 4 meters wide.
The laying of the pipeline of our system always starts from the smaller side, that is, from the width.
To create the basis of the pipeline, we take 15 pipes.
A gap of 10 cm remains near the walls, which then increases on each side by 5 cm.
The section between the pipeline and the collector is 40 cm. This distance exceeds the 20 cm from the wall that we talked about above, since a water drainage channel will have to be installed in this section.

Our indicators now make it possible to calculate the length of the pipeline: 15x3.4 \u003d 51 m. The entire circuit will take 56 m, since we should also take into account the length of the so-called. collector section, which is 5 m.

The length of the pipes of the entire system must fit into the allowable range - 40-100 m.

Quantity

One of following questions: what is the maximum length of the water floor heating circuit? What to do if the room requires, for example, 130, or 140-150 m of pipe? The way out is very simple: it will be necessary to make more than one contour.

In the operation of a water-heated floor system, the main thing is efficiency. If, according to calculations, we need 160 m of pipe, then we make two circuits of 80 m each. After all, the optimal length of the contour of a water-heated floor should not exceed this indicator. This is due to the ability of the equipment to create the necessary pressure and circulation in the system.

It is not necessary to make the two pipelines absolutely equal, but it is also not desirable that the difference be noticeable. Experts believe that the difference may well reach 15 m.

Maximum length of the water floor heating circuit

To determine this parameter, we must consider:

The listed parameters are determined, first of all, by the diameter of the pipes used for the warm water floor, the volume of the coolant (per unit of time).

In the installation of a warm floor, there is a concept - the effect of the so-called. locked loop. This is a situation where circulation through the loop will not be possible, regardless of the pump power. This effect inherent in a pressure loss situation of 0.2 bar (20 kPa).

In order not to confuse you with long calculations, we will write a few recommendations that have been proven by practice:

The maximum contour of 100 m is used for pipes with a diameter of 16 mm made of metal-plastic or polyethylene. Perfect option– 80 m
A contour of 120 m is the limit for a 18 mm pipe made of cross-linked polyethylene. However, it is better to limit yourself to a range of 80-100 m
With 20 mm plastic pipe, you can make a circuit of 120-125 m

Thus, the maximum length of a pipe for a warm water floor depends on a number of parameters, the main of which is the diameter and material of the pipe.

Are two identical ones necessary and possible?

Naturally, the situation will look ideal when the loops have the same length. In this case, you will not need any settings, the search for balance. But it's in more in theory. If you look at practice, it turns out that it is not even advisable to achieve such a balance in a warm water floor.

The fact is that it is often necessary to lay a warm floor at an object consisting of several rooms. One of them is emphasized small, for example - a bathroom. Its area is 4-5 m2. In this case, a reasonable question arises - is it worth adjusting the entire area for a bathroom, splitting it into tiny sections?

Since this is not advisable, we come to a different question: how not to lose on pressure. And for this, elements such as balancing fittings have been created, the use of which consists in equalizing pressure losses along the contours.

Again, calculations can be used. But they are complex. From the practice of carrying out work on the installation of a warm water floor, we can safely say that the spread in the size of the contours is possible within 30-40%. In this case, we have every chance to get maximum effect from the operation of a warm water floor.

Despite the considerable amount of materials on how to make a water floor on your own, it is better to turn to specialists. Only masters can evaluate the working area and, if necessary, “manipulate” the pipe diameter, “cut” the area and combine the laying step when we are talking about large areas.

Quantity with one pump

Another frequently asked question: how many circuits can operate on one mixing unit and one pump?
The question really needs to be clarified. For example, to the level - how many loops can be connected to the collector? In this case, we take into account the diameter of the collector, the volume of the coolant passing through the node per unit of time (the calculation is in m3 per hour).

We need to look at the data sheet of the node, where the maximum coefficient is indicated bandwidth. If we carry out calculations, then we will get the maximum indicator, but we cannot count on it.

One way or another, the maximum number of circuit connections is indicated on the device - as a rule, 12. Although, according to calculations, we can get both 15 and 17.

The maximum number of outlets in the collector does not exceed 12. Although there are exceptions.

We saw that installing a warm water floor is a very troublesome business. Especially in that part of it, where we are talking about the length of the contour. Therefore, it is better to contact specialists so as not to redo later a not entirely successful styling that will not bring the efficiency that you expected.

Underfloor heating is one of the most efficient and cost-effective ways of space heating. Judging from the standpoint of operating costs, the water "warm floor" looks preferable, especially if the house already has a water heating system. Therefore, despite the rather high complexity of installation and debugging of water heating, it is often chosen.

Work on a water "warm floor" begins with its design and calculations. And one of the most important parameters will be the length of the pipes in the circuit being laid. The point here is not only, and not so much in the cost of material - it is important to ensure that the length of the contour does not exceed the allowable maximum values, otherwise the performance and efficiency of the system is not guaranteed. To help with the necessary calculations, the calculator for calculating the length of the contour of a water-heated floor, located below, will be able to help.

A few necessary explanations for working with the calculator are given below it.

Warm floor perfect solution to improve your home. The floor temperature directly depends on the length of the underfloor heating pipes hidden in the screed. The pipe in the floor is laid in loops. In fact, the total length of the pipe is added up from the number of loops and their length. It is clear that the longer the pipe in the same volume, the warmer the floor. In this article, we will talk about restrictions on the length of one contour of a warm floor.

Approximate design characteristics for pipes with a diameter of 16 and 20 mm are: 80-100 and 100-120 meters, respectively. These data are approximate for approximate calculations. Let's take a closer look at the process of installing and pouring underfloor heating.

Consequences of exceeding the length

Let's figure out what consequences an increase in the length of the underfloor heating pipe can lead to. One of the reasons is an increase in hydraulic resistance, which will create an additional load on the hydraulic pump, as a result of which it may fail or simply may not cope with the task assigned to it. The resistance calculation consists of many parameters. Conditions, styling parameters. The material of the pipes used. Here are the three main ones: loop length, number of bends and thermal load on it.

It is worth noting that the thermal load increases with the increase in the loop. The flow rate and hydraulic resistance also increase. There are restrictions on the flow rate. It should not exceed 0.5 m/s. If we exceed this value, various noise effects may occur in the piping system. The main parameter, for the sake of which this calculation is made, also increases. The hydraulic resistance of our system. It also has limitations. They are 30-40 kP per loop.

The next reason is that with an increase in the length of the underfloor heating pipe, the pressure on the pipe walls increases, causing this section to elongate when heated. The pipe in the screed has nowhere to go. And it will begin to narrow at its weakest point. The constriction can cause blockage of the flow in the coolant. For pipes made from different material, different expansion coefficient. For example, at polymer pipes expansion coefficient is very high. All these parameters must be taken into account when installing a warm floor.

Therefore, it is necessary to fill in the underfloor heating screed with pressed pipes. It is better to pressurize with air with a pressure of about 4 bar. Thus, when you fill the system with water and start heating it, the pipe in the screed will expand somewhere.

Optimum pipe length

Taking into account all the above reasons, taking into account the corrections for the linear expansion of the pipe material, we take as a basis the maximum length of the underfloor heating pipes per circuit:

The table shows optimal dimensions underfloor heating lengths that are suitable for all modes of thermal expansion of pipes in various operating modes.

Note: In residential buildings 16 mm pipe is enough. Larger diameter should not be used. This will lead to unnecessary spending on energy.

The main argument in favor of the "warm floor" system is the increased comfort of a person's stay in the room, when, as heater the entire surface of the floor protrudes. The air in the room warms up from the bottom up, while at the floor surface it is somewhat warmer than at a height of 2-2.5 m.

In some cases (for example, when heating shopping malls, swimming pools, sports halls, hospitals), underfloor heating is the most preferable.

To the disadvantages of systems floor heating are relatively high, in comparison with radiators, the cost of equipment, as well as increased requirements for the technical literacy of installers and the quality of their work. Using quality materials and compliance with the installation technology of a well-designed water floor heating system, there are no problems during its subsequent operation.

The heating copper works on radiators in the mode 80/60 °C. How to connect the "warm floor"?

To obtain the design temperature (as a rule, not higher than 55 ° C) and the specified coolant flow rate in the "warm floor" circuit, pumping and mixing units are used. They form a separate low-temperature circulation circuit, into which the hot coolant from the primary circuit is mixed. The amount of mixed coolant can be set either manually (if the temperature and flow in the primary circuit are constant) or automatically using temperature controllers. Fully realize all the advantages of the "warm floor" allow pumping and mixing units with weather compensation, in which the temperature of the coolant supplied to the low-temperature circuit is adjusted depending on the outside temperature.

Is it allowed to connect a "warm floor" to the central heating or hot water system of an apartment building?

It depends on local legislation. For example, in Moscow, the installation of underfloor heating from common house water supply and heating systems is excluded from the list of permitted types of re-equipment (Decree of the Government of Moscow No. 73-PP of February 8, 2005). In a number of regions, interdepartmental commissions decisive question approvals for the installation of the "warm floor" system, require additional expertise and calculated confirmation that the "warm floor" device will not lead to disruption in the operation of common house engineering systems(see "Rules and regulations technical operation housing stock", clause 1.7.2).

From a technical point of view, the connection of a "warm floor" to the central heating system is possible provided that a separate pumping and mixing unit is installed with a limitation of the pressure returned to house system coolant. In addition, if there is an individual heating point in the house equipped with an elevator (jet pump), the use of plastic and metal-plastic pipes in heating systems is not allowed.

What material is better to use as a floor covering in the "warm floor" system? Can parquet floors be used?

Best of all, the effect of "warm floor" is felt when floor coverings from materials with a high coefficient of thermal conductivity ( ceramic tile, concrete, self-leveling floors, baseless linoleum, laminate, etc.). If carpet is used, it must have a "suitability mark" for use on a warm base. Other synthetic coatings(linoleum, relin, laminated boards, plastic compound, PVC tiles, etc.) must have a “no sign” of toxic emissions at elevated base temperatures.

Parquet, parquet boards and boards can also be used as floor heating, but the surface temperature should not exceed 26 °C. In addition, a safety thermostat must be included in the mixing unit. Moisture content of floor covering materials natural wood should not exceed 9%. Works on laying parquet or plank flooring may only be carried out at a room temperature of at least 18 ° C and 40-50% humidity.

What should be the temperature on the surface of the "warm floor"?

The requirements of SNiP 41-01-2003 "Heating, ventilation and air conditioning" (clause 6.5.12) regarding the surface temperature of the "warm floor" are given in the table. It should be noted that foreign regulations allow several big values surface temperatures. This must be taken into account when using calculation programs developed on their basis.

How long can the pipes of the "warm floor" circuit be?

The length of one loop of the "warm floor" is dictated by the power of the pump. If we talk about polyethylene and metal-plastic pipes, then it is economically feasible that the length of a pipe loop with an outer diameter of 16 mm does not exceed 100 m, and with a diameter of 20 mm - 120 m. It is also desirable that the hydraulic pressure loss in the loop does not exceed 20 kPa. The approximate area occupied by one loop, subject to these conditions, is about 15 m2. At larger area collector systems are used, while it is desirable that the length of the loops attached to one collector be approximately the same.

What should be the thickness of the heat-insulating layer under the pipes of the "warm floor"?

The thickness of the thermal insulation, which limits the heat loss from the "underfloor heating" pipes in the "down" direction, should be determined by calculation and largely depends on the air temperature in the design room and the temperature in the underlying room (or soil). In most Western calculation programs, heat losses "down" are taken in the amount of 10% of the total heat flow. If the air temperature in the calculated and underlying room is the same, then this ratio is satisfied by a layer of expanded polystyrene 25 mm thick with a thermal conductivity coefficient of 0.035 W / (mK).

What pipes are better to use for the installation of the "warm floor" system?

Pipes for a "warm floor" device must have the following properties: flexibility, allowing the pipe to be bent with a minimum radius to ensure the required laying step; the ability to keep the shape; low coefficient of resistance to the movement of the coolant to reduce the power of pumping equipment; durability and corrosion resistance, since access to pipes during operation is difficult; oxygen impermeability (like any pipeline heating system). In addition, the pipe must be easy to process a simple tool and have a reasonable price.

The most widespread systems are "warm floor" made of polyethylene (PEX-EVOH-PEX), metal-plastic and copper pipes. Polyethylene pipes are less convenient in work, because they do not retain the given shape, and when heated, they tend to straighten up ("memory effect"). Copper pipes, when embedded in a screed, must have a polymer coating to avoid alkaline exposure, moreover, this material is quite expensive. Metal-plastic pipes most fully meet the requirements.

Do I need to use a plasticizer when pouring a "warm floor"?

The use of a plasticizer makes it possible to make the screed more dense, without air inclusions, which significantly reduces heat losses and increases the strength of the screed. However, not all plasticizers are suitable for this purpose: most of those used in construction are air-entraining, and their use, on the contrary, will lead to a decrease in the strength and thermal conductivity of the screed. For "warm floor" systems, special non-air-entraining plasticizers are produced, based on finely dispersed scaly particles of mineral materials with a low coefficient of friction. As a rule, the consumption of the plasticizer is 3-5 l/m3 of solution.

What is the point of using aluminum foil coated thermal insulation?

In cases where the pipes of the "warm floor" are installed in air gap(for example, in floors along logs), foiling thermal insulation allows you to reflect most of the downward radiant heat flux, thereby increasing the efficiency of the system. Foil plays the same role in the construction of porous (gas or foam concrete) screeds.

When the screed is made of dense cement-sand mixture, thermal insulation foiling can be justified only as an additional waterproofing - the reflective properties of the foil cannot manifest themselves due to the lack of an air-solid body boundary. It must be borne in mind that the layer of aluminum foil poured cement mortar, must have protective covering from a polymer film. Otherwise, aluminum can be destroyed under the influence of a highly alkaline environment of the solution (pH = 12.4).

How to avoid cracking of the "warm floor" screed?

The reasons for the appearance of cracks in the "warm floor" screed may be the low strength of the insulation, poor-quality compaction of the mixture during installation, the absence of a plasticizer in the mixture, too thick a screed (shrinkage cracks). The following rules should be followed: the density of the insulation (expanded polystyrene) under the screed must be at least 40 kg/m3; the screed mortar must be workable (plastic), the use of a plasticizer is mandatory; in order to avoid the appearance of shrinkage cracks, polypropylene fiber should be added to the solution at the rate of 1-2 kg of fiber per 1 m3 of solution. Steel fiber is used for load-bearing floors.

Is waterproofing required for underfloor heating?

If a vapor barrier device is not provided for in the architectural and construction part of the project, then with the "wet method" of installing the "warm floor" system on floors, it is recommended to lay a layer of glassine over the leveled floor. This will help prevent laitance from leaking through the overlap during pouring of the screed. If the project provides for interfloor vapor barrier, then it is not necessary to arrange additional waterproofing. Waterproofing in wet areas (bathrooms, lavatories, showers) is arranged in the usual way over the "warm floor" screed.

What should be the thickness of the damper tape installed around the perimeter of the room?

For rooms with a side length of less than 10 m, it is sufficient to use a seam with a thickness of 5 mm. For other rooms, the calculation of the seam is carried out according to the formula: b \u003d 0.55 o L, where b is the thickness of the seam, mm; L is the length of the room, m.

What should be the step of laying the pipes of the "warm floor" loop?

The step of the loops is determined by calculation. It should be borne in mind that a loop pitch of less than 80 mm is difficult to implement in practice due to the small bending radius of the pipe, and a pitch of more than 250 mm is not recommended, as it leads to a noticeable uneven heating of the "warm floor". To facilitate the task of choosing the loop pitch, you can use the table below.

Is it possible to install heating only on the basis of the "warm floor" system, without radiators?

To answer this question in each case, it is required to make a thermal calculation. On the one hand, the maximum specific heat flow from the "warm floor" is about 70 W/m2 at an air temperature in the room of 20 °C. This is sufficient to compensate for heat losses through enclosing structures made in accordance with thermal protection standards.

On the other hand, if we take into account the heat costs for heating the required sanitary standards outdoor air (3 m3 / h per 1 m2 of living space), then the capacity of the "warm floor" system may be insufficient. In such cases, the use of edge zones with elevated surface temperatures along the outer walls, as well as the use of sections of "warm walls" is recommended.

How soon after pouring the screed can I start the "warm floor" system?

The screed must have time to acquire sufficient strength. After three days under natural hardening conditions (without heating), it gains 50% strength, after a week - 70%. Full curing to the design grade occurs after 28 days. Based on this, it is recommended to start the "warm floor" no earlier than three days after pouring. You also need to remember that the filling of the "warm floor" system with a solution is carried out with floor pipelines filled with water at a pressure of 3 bar.

1. What temperature should the coolant be in the warm floor and how can its temperature be controlled?

The temperature should not be higher than 55 ° C, and in some cases not higher than 45 ° C.

To put it even more precisely: the temperature should be in accordance with the temperature calculated in the project, which takes into account the need for a particular room in heat and the material from which the finished floor is made.

You can control the temperature with the help of such a thermometer, and preferably two.

One thermometer shows the temperature of the heat carrier at the underfloor heating supply (temperature mixed water), and the other is the return temperature.

If the difference between the readings of two thermometers is 5 - 10 ° C, then the underfloor heating system is working correctly for you.

2. What should be the temperature on the surface of the warm floor?

The surface temperature of a working underfloor heating must not exceed the following values:

29 ° C - in the premises of long-term stay of people;

35 o C - in the boundary zones;

33 o C - in bathrooms, bathrooms.

3. What forms of pipe laying are used for underfloor heating?

For laying underfloor heating pipes different forms: snake, corner snake, snail, double snake (meander).

Also, when laying one contour, you can combine these forms.

For example, the edge zone can be arranged with a snake, and then the main part can be passed with a snail.

4. What is the best installation for underfloor heating?

For large square, rectangular or round rooms without geometric exclusivity, it is better to use a snail.

For small rooms, rooms with complex shapes or long rooms, use a snake.

5. What should be the laying step?

The laying step must be designed in accordance with the calculations.

For edge zones, a step of 10 cm is used. For other zones with a difference of 5 cm - 15 cm, 20 cm, 25 cm. But not more than 30 cm.

This limitation is due to the sensitivity of the human foot.
With a larger pipe pitch, the foot begins to feel the temperature difference in the floor sections.

To do this, you can use a very simple formula: L=S/N*1.1, where

S is the area of \u200b\u200bthe room or circuit for which the pipe length is calculated (m 2);
N - laying step;
1.1 - pipe margin of 10% for turns.

To the result, do not forget to add the length of the pipe from the collector to the underfloor heating, including supply and return.

For example, consider a problem in which you need to calculate the length of a pipe for a room in which the floor occupies a usable area of 12 m 2. The distance from the collector to the warm floor is 7 m. The pipe laying step is 15 cm (do not forget to convert to m).

Solution: 12 / 0.15 * 1.1 + (7 * 2) = 102 m.

7. What is the maximum length of one loop?

Everything depends on the hydraulic resistance or pressure losses in a particular circuit, which, in turn, directly depend on both the diameter of the pipes used and the volume of coolant that is supplied through the cross section of these pipes per unit time.

In the case of a warm floor, (if you do not take into account the above factors), you can get the effect of the so-called locked loop. A situation in which no matter how powerful the pump you install in terms of pressure, circulation through this loop will be impossible.

In practice, it has been found that pressure losses of 20 kPa or 0.2 bar just lead to this effect.

In order not to go into calculations, we give some recommendations that we use in practice.
For metal-plastic pipe With a diameter of 16 mm, we make a contour no more than 100 m. Usually we stick to 80 m.
The same applies to polyethylene pipes. For 18 XLPE pipes, the maximum loop length is 120 m. In practice, we adhere to 80 - 100 m. For 20 metal-plastic pipes, the maximum loop length is 120 - 125 m.

8. Can there be underfloor heating contours of different lengths?

The ideal situation is when all loops are the same length. You don't need to balance or adjust anything.

In practice, this can be achieved, but most often it is not advisable.

For example, at the facility there is a group of rooms where you need to make a warm floor. Among them there is also a bathroom, the usable floor area of which is 4 m 2 . Accordingly, the length of the pipeline of this circuit, together with the length of the pipes to the collector, is only 40 m.
Do all rooms really need to be adjusted to this length, splitting the usable area of the remaining rooms by 4 m 2?

Of course not. This is not advisable. And then what is the balancing valve for, which is precisely designed to help equalize the pressure loss along the contours?

Again, you can use the calculations through which you can see to what maximum limit you can allow the spread of pipe lengths of individual circuits at a particular facility with this equipment.

But again, without plunging you into complex boring calculations, let's say that at our facilities we allow a spread in the lengths of pipes of individual circuits of 30 - 40%. Also, if necessary, you can "play" with pipe diameters, laying steps and "cut" the areas of large rooms not into small or large, but into medium pieces.

9. How many circuits can be connected to one mixing unit with one pump?

This question for physical meaning similar to the question: "How much cargo can you take away by car?"

What else would you like to know if someone asked you this question?

Absolutely right. You would ask: "What car are we talking about?"

Therefore, in the question: “How many loops can be connected to the underfloor heating collector?”, It is necessary to take into account the diameter of the collector and what volume of coolant is able to pass through the mixing unit per unit of time (it is customary to consider m 3 / hour). Or, which is also equivalent, what kind of heat load can the mixing unit of your choice carry?

How to find out? Very simple.

For clarity, let's show an example.

Let's say you have chosen Valtec's Combimix as your mixing unit. What heat load is it designed for? We take his passport. See the clipping from the passport.

What do we see?

Its maximum flow rate is 2.38 m 3 /hour. If we put the Grundfos UPS 25 60 pump, then at the third speed with this coefficient this unit is able to "drag" a load of 17000 W or 17 kW.

What does this mean in practice? 17 kW is how many circuits?

Imagine that we have a house in which there are some (unknown) rooms of 12 m 2 of usable floor space in each room. Our pipes are laid in increments of 20 cm, which leads to the length of each circuit, taking into account the length of the pipes from the warmest floor to the collector, 86 m. In accordance with the design calculations, we also found that the heat removal from each m 2 of this warm floor gives 80 W , which leads us respectively to the thermal load of each circuit

12 * 80 = 960 W

How many rooms or similar circuits can our mixing unit provide with heat?

17000 / 960 = 17.7 similar circuits or rooms.

But this is the maximum!

In practice, in most cases, it is not necessary to calculate the maximum performance. So let's stick with number 15.

Valtec itself has a collector with the maximum number exits - 12.

10. Do I need to make several contours of the warm floor in large rooms?

In large rooms, the design of the warm floor must be divided into smaller areas and several contours should be made.

This need arises for at least two reasons:

limiting the length of the circuit pipe is necessary in order not to get the effect of a "locked loop", in which there will be no coolant circulation through it;

the correct operation of the cement slab itself, the area of \u200b\u200bwhich should not exceed 30 m 2. WITHthe ratio of the lengths of its sides should be 1/2 and the length of one of the edges should not exceed 8 m.

11. How do I know how many underfloor heating circuits I need for my house?

In order to understand how many loops of a warm floor will be needed and, on the basis of this, to choose a suitable collector with the same number of outlets, you need to start from the area of \u200b\u200bthe premises themselves in which this system is planned.

After that, you calculate the useful area of \u200b\u200bthe warm floor. How to do this is described in question 12 " How to calculate the usable floor area?".

Then, use the following method: starting from the step of the warm floor, break the usable area of the warm floor in each room into the following dimensions:

step 15 cm - no more than 12 m 2;
step 20 cm - no more than 16 m 2;
step 25 cm - no more than 20 m 2;
step 30 cm - no more than 24 m 2.

If the floor area in the room is less than the specified dimensions, then it does not need to be broken.
We recommend reducing these values by 2 m 2 if the length of the pipe connection from the underfloor heating to the collector exceeds 15 m.
When dividing the useful floor area in the premises, also try to ensure that the length of the pipes in these circuits is either the same, or the difference between the individual circuits does not exceed 30 - 40%.How to find out the length of pipes in each circuit, read question 6 " How to calculate pipe length?".

Step back 30 cm from each of the walls of the room. Shade the resulting space. Mark on the plan the areas where the furniture will constantly stand: a refrigerator, furniture wall, sofa, large closet, etc. Shade these areas as well. The unshaded part of the room plan will be the usable floor area you are looking for.

For clarity, let's calculate the useful area of the dining room, where there will be a warm floor. The total area of the dining room is 20 m 2, the length of the walls is 4 m and 5 m, respectively. The kitchen will have kitchen set, refrigerator and sofa, which we will mark on the plan. Let's not forget to step back from the walls by 30 cm. Let's shade the occupied areas. See drawing.

And now let's calculate the usable floor area.

13. What is the total thickness of the underfloor heating cake?

It all depends on the thickness of the insulation, since the remaining values \u200b\u200bare known.

With the next thickness of the insulation, you will get the following values (the thickness of the finishing coating is not taken into account):

3 cm - 9.5 cm;
8 cm - 14.5 cm;
9 cm - 15.5 cm.

14. What do you use to calculate the water floor heating system?

For the calculation of both radiator heating systems and underfloor heating systems, we use the company's Audytor CO program.

Below we post a screenshot of the module of this program for the preliminary calculation of a warm floor and a screenshot of the module for calculating the layers of a warm floor pie.

Upon careful consideration of these screenshots, you can understand how serious the correct calculation of the warm floor is.

You can also see the work of the program itself, which does possible visual control over such important parameters like pipe length, pressure loss, floor surface temperature, heat going down uselessly, useful heat flow, etc.

15. How to determine the dimensions of the collector cabinet in order to place all the necessary components in it?

Determining the dimensions of the collector cabinet is not difficult. We once again invite you to use Valtec products and their ready-made recommendations presented in the table, provided that you are using ready-made underfloor heating units manufactured by this manufacturer.

Linear dimensions of manifold cabinet

(SHRN - external; SHRV - internal)

Model	Length, mm	Depth, mm	Height, mm
SHRV1	670	125	494
SHRV2	670	125	594
SHRV3	670	125	744
SHRV4	670	125	894
SHRV5	670	125	1044
SHRV6	670	125	1150
SHRV7	670	125	1344
SHRN1	651	120	453
SRN2	651	120	553
SHRN3	651	120	703
SRN4	651	120	853
SHRN5	651	120	1003
SHRN7	658	121	1309

Selection of manifold cabinet

Collector groups 1 (VT.594, VT59)	cabinet model SHRN/SHRV + Combimix+ ball valve	cabinet model SHRN/SHRV + Dualmix + ball valve	cabinet model SHRN / SHRV + crane
Collector 1*3out	SHRN3/SHRV3	SHRN4/SHRV4	SHRN1/SHRV1
Collector 1*4out	SHRN3/SHRV3	SHRN4/SHRV4	SHRN2/SHRV2
Collector 1*5out	SHRN4/SHRV3	SHRN5/SHRV4	SHRN2/SHRV2
Collector 1*6out	SHRN4/SHRV4	SHRN5/SHRV5	SHRN3/SHRV3
Collector 1*7out	SHRN4/SHRV4	SHRN5/SHRV5	SHRN3/SHRV3
Collector 1*8out	SHRN5/SHRV4	SHRN6/SHRV5	SHRN3/SHRV3
Collector 1*9out	SHRN5/SHRV5	SHRN6/SHRV6	SHRN4/SHRV4
Collector 1*10out	SHRN5/SHRV5	SHRN6/SHRV6	SHRN4/SHRV4
Collector 1*11out	SHRN6/SHRV5	SHRN7/SHRV6	SHRN4/SHRV4
Collector 1*12out	SHRN6/SHRV6	SHRN7/SHRV7	SHRN5/SHRV5

16. At what height should the manifold cabinet be installed?

There are no specific rules in this regard, but there are recommendations.

On the one hand, it is clear that when mounting a collector cabinet, it is necessary to take into account the height of the future screed and finish, so that a situation does not turn out when it will not even be possible to open the cabinet door.

On the other hand, serviceability and the need to possible replacement individual elements systems with the possibility of pipeline disconnection.

The shorter the pipe section, the greater its rigidity and vice versa.

Considering this factor, it is possible to raise the collector cabinet by 20 - 25 cm from the level of the finished floor.

However, we must not forget about a very important design element. If lifting the cabinet leads to an unacceptable violation of the design and it is impossible to solve this problem in another way, lower the cabinet to the floor level, but in such a way that it can open.