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How to calculate the pump for the floor heating

How to choose?

In order not to make a wrong choice, it is necessary to study the advice of professionals, which we have picked up for you:

  • The pump must be purchased together with all the constructional elements of the future system. This will maximise the efficiency of the system and ensure its longevity. Repair work will be expensive, so it is better to protect yourself.
  • The pump selection should be based on the capacity of the unit. This parameter can indicate the capacity in liters or cubic meters. It all depends on the amount of heat transfer fluid that will be in the system. Multiply this by 3 to obtain the required pump capacity.
  • the head needs to be matched with the parameters of the pipes that make up the system (diameter, length, material).
  • A small pump is easier to locate indoors, but the size of the unit is directly related to its capacity. Small pump. limited capacity.
  • The phase also influences the choice of pump. Usually for private facilities choose single-phase units. But industrial areas require the installation of pumps with a three-phase motor.
  • Foreign pumps are not always better than domestic counterparts. Products of our manufacturers are designed for low water quality and peculiarities of use, typical for our area.

What material and equipment marking to choose?

The marking consists of three or two digits, which denote:

  • Diameter of holes in millimeters (inlet and outlet);
  • height of the heat carrier lift provided by the device
  • The total length of the entire unit.

calculate, pump, floor, heating

The choice of pump for a warm water floor also takes into account the type of material. With the right selection of pipes with the type of material should not be a problem. Difficulties appear if in the process of drawing up the scheme was not considered the level of oxygen permeability. In this case, the installation of a cast iron housing is strictly contraindicated. The active oxidizer will destroy the material, which will lead to a rapid failure of the entire system.

An alternative option will be stainless steel or polymers. If you do not know how to choose a pump for a warm water floor, then buy equipment from a European manufacturer. So you can eliminate the risk of marriage and significantly prolong the life of the system. Do not skimp on the purchase of such an installation, as your well-being and comfort depends on it.

Features of connecting a warm floor without a mixing unit

A common misstep when installing a system with no mixing unit is the installation on very large room sizes.

The main requirements for installation:

  • The walls in the room must be insulated (outside or inside);
  • On the floor must be laid thermal insulation;
  • High-quality double-glazed windows;
  • Install the floor near the heating system;
  • Room area is no larger than 25 m2.

Disadvantages of the system without a manifold:

High heat loss on the way from the heater and the pipeline unit itself. Accordingly, it is necessary to save heat on the floor surface.

Competent calculation of the circuit length and circuit, so that the return temperature is not too low. Otherwise, a lot of condensation is formed during the heat exchange of the boiler, which can quickly disable the device.

Installation of a condensing boiler with high efficiency helps when the “return” is cold, the device is not affected by low temperatures during heating.

Assembling methods

The elementary principle of assembly is to connect the underfloor heating design to the central heating. The disadvantage of such a system is the risk of breakage of the underfloor heating piping due to the high temperature of water in the radiators.

Independently constructed construction, which is connected to the central heating point, can be fined and dismantled by the supervisory authorities upon detection.

The two best ways to lay pipes without a mixing unit:

  • Serpent helps to distribute heating areas (around furniture or plumbing);
  • the volute promotes uniform heating of the floor area.

Both methods should be designed from a double piping system. for supply and return water.

After the pipeline is laid it is connected to the boiler. The pump of the right power will ensure the speed of the heating element in the pipeline.

Pump models can be manually or automatically controlled. The device is placed on the supply side of the pipe. If there is no collector in the system the pump is placed under the boiler.

The connecting construction is completed by the valve, which should be installed between the pipe and the pump.

For the stable operation of the underfloor heating without a manifold, it is recommended to choose a good-quality electric or gas boiler with not a small capacity.It is better to buy the boiler complete with a pump. Differences in the design of radiator heating and water underfloor heating

  • Radiator heating is characterized by high temperatures of the coolant, the supply temperature is approximately 70 degrees, and the return temperature is 50 ° C. Mounting features. the pump is not installed on the supply side, so as to avoid the risk of overheating.
  • The floor temperature during heating should not exceed 26-30 ° C, the comfortable temperature for the gentle operation of the pump is 40 ° C.
  • Circulation speed radiator heating is not great, because of the temperature drop is enough to install a boiler with a pump built into it.
  • Thin plastic pipes are the radiator for underfloor heating. The length of the pipes can reach more than a hundred meters in one installation system. Accordingly, the pumping device must be powerful enough to push the water through the pipes.

System with a three-way valve

Thermostatic valve assembly (three-way) is made on the heat supply pipes, to the opposite flow is connected jumper.

This device regulates the temperature of the heat supply, which is brought to the pump. The valve functions like a mixer with a temperature-sensitive element.

The advantages of the valve is to protect the system from too high temperatures (overheating) and if necessary during a breakdown, it will automatically shut off the heating medium and return flow. Thanks to this valve assumes part of the work of the mixing unit.

When the floor area is too large, there can be large heat losses on the return of the coolant. Therefore it is better to install a valve at the edge with a cold inlet this will have the effect that there is no excessive condensation in the heat exchange unit.

Choose a pump

You can do without a mixing valve? You can, but you can hardly do without a pump. Circulation station will increase the pressure and warm the water evenly, will not make excessive pressure, and will push the water at the required speed.

Before choosing a pump, you need to decide on the company, model, and the material of which it is made of.

Two types of equipment are recommended for use in domestic conditions:

  • Wet Rotor Pump. This technique does not have a large capacity, but can provide operation of the floor with heating, the area of which is equal to 350-400 m2. The rotor has the “wet” name because of the wheel located in the coolant, cooling and lubrication takes place when using it. The device is popular due to its quiet operation, reliability and economical power consumption.
  • Model with a dry rotor is a fairly powerful device, in which the rotor is located in an impermeable container. This type of equipment is used for the arrangement of fountains in private homes or park areas. Model requires periodic maintenance.

Choosing the right pump for your underfloor heating system

How to choose a pump for underfloor heating? Most CO pumps on the market today have a standardized flow rate of around 40 l/min (approx. 2.5 cu.m.).m / h) and the head up to six meters. Flow rate is directly proportional to head value.

When buying, you should understand that the flow rate indicated on the pump in 40 liters per minute will not always correspond to the actual flow. Т.к. the latter depends on the capacity of the floor or the system itself. A large number of long circuits reduces the flow rate.

This is easy to understand from the two graphs: the theoretical graph (for all such pumps). and the real one for the 2.5 cc pump discussed in the example.м. with a head of six meters



The higher the flow capacity of your system, the weaker the head on all connected circuits. Т.е., The more circuits are closed on one mixing unit, the higher the flow rate.

A pump for underfloor heating: types and selection rules

Underfloor heating has long ceased to be a unique phenomenon, today it is available to everyone, with the necessary literature and the acquired knowledge to install it yourself without engaging professionals. This system is gaining popularity: It’s now being installed not only in private homes, but in apartments as well. Systems of water floor heating are advantageous economical in operation, but expensive to install. Therefore, it is necessary to correctly select all components, one of which is a water pump.

The most important thing. to make a correct calculation and perform all installation work in accordance with the instructions.

How to install the pump on the floor heating

Once the location is selected, you should proceed with the installation. The algorithm of action is as follows:

  • First install the bypass. a bypass pipe in the place to be installed.
  • To do this you need to cut the main pipe.
  • Form a thread on its ends.
  • Install the ball valve and install the pump.
  • Open the tap for water access.
  • Open the screw to bleed air.
  • After installing the circulating pump to the floor heating must be sure to test the system. First, the work is checked at low speed.

Scheme of the correct installation pump for underfloor heating

The most suitable floor coverings

A warm floor can be arranged with different floor coverings. However, for each room, the choice must be made after familiarizing yourself with the operating characteristics.

Ceramic tiles are more suitable for bathrooms, as they can withstand the effects of humid environment. Most often the screed is poured, into which the pipes or cables of the system are inserted, and the tiles are laid on top. With additional heating, tiles lose their main disadvantage. their cold surface.

For the kitchen, linoleum may be a good option for finishing the floor. It is often chosen together with a film floor that emits infrared radiation. The elements in this case are placed on top of the screed. Plywood, particle board or OSB are laid on them. Linoleum is laid on top.

In the same way a heating system is created in combination with laminate. However, it is not necessary to underlay additional substrate. Panels can be mounted on top of the film.

If necessary, you can implement additional heating directly under the carpet. However, it is better to use it in the bedroom to increase the heat effect. The main disadvantage of coating. the difficulty in removing impurities.

In what cases you can do without the pump

The movement of the coolant in the circuit can occur due to the laws of physics. That is, the heated working fluid goes up and the cooled fluid goes down. This is how the room is heated, so the floor heating works without the pump from the boiler.

Such systems are mostly used in country houses or summer cottages. This is due to the fact that in suburban conditions, electricity is not always stable or there is none. Therefore, it is not always advisable to use equipment with forced circulation.

On the Internet resources of companies that are engaged in the installation of such equipment, you can find a wiring diagram of the pump for floor heating.

Many owners of country houses, after reading and hearing about the benefits that give water “heat-insulated floors”, are seriously thinking about the independent creation of such a system of heating. It should be said at once: this task. extremely complex, large-scale, requiring the mobilization of all their skills and abilities in both general construction issues, and in plumbing installation. It is necessary to take special care in the selection of all components, which in turn must meet a number of important requirements.

In order to ensure equal heating of the floors pipes are placed at a small distance from each other (100-200 mm). The distance between the pipes near the walls is less than in the center of the room. Laying of pipes is carried out according to two schemes:

The heat carrier warmed up to a temperature of 35-45 degrees, passing through the pipeline, loses its temperature. Optimal length of the pipeline (loop) up to 120 m. This is enough to cover an area of up to 20 m2. For large rooms, several pipelines are installed. They are connected to the heat source in parallel through the collector, which is located in a special cabinet. Shut-off and control and regulating devices (manometers, thermostats, drain valves, flow sensors, air valves) and pumps are installed in the same cabinet.

How to choose a circulation pump for a warm floor by the calculated head

Since the head is overcome by the hydraulic resistance of all system elements, you need to consider these figures personally:

  • the material and diameter of the pipe affect the resistance, see the instructions for the unit;
  • coefficient of resistance increase at the valve. 1.7;
  • coefficient of resistance on fittings and fittings. 1.2;
  • resistance coefficient at the mixing unit. 1.3.

The formula for calculating the head is as follows: H=(PxLEC)/1000 where:

  • H-pressure of the unit;
  • P. resistance of 1 m of the linear pipe;
  • Pa/m,L-length of longest loop, m;
  • K- coefficient of power reserve.

The length of the circuit multiplied by the resistance coefficient in 1 m of the pipe. convert the reading in kilopascals (kPa) to atmospheres 100 kPa = 0.1atm. Multiply the result by the resistance coefficients of all the elements in the system. The result is the operating point of the unit.

Then find the characteristic, made graphically by a catalog or passport models. The operating point of the correctly selected model must be in the middle third of the graph. When a 3-speed unit is installed, the pump is selected for the 2nd speed, which will allow to operate the pump in an optimal mode.

How to choose a pump by calculating the volume of coolant

Usually, the selection of the required unit is made by installation specialists, but you can do it individually, making some calculations. We perform them according to the formula Q=0.86xPn/(T n.Тob), where

  • Q. volume of heat carrier, in cubic meters per hour;
  • 0,86.conversion coefficient;
  • Pn. power of the underfloor heating circuit required for compensation for heat losses;
  • (Tn-Tob). difference between the temperatures of the coolant entering the pipe-line system and leaving it via return pipes.

Initial data of heat losses and temperatures are taken from construction reference books. This is how we know the volume flow rate of the heat transfer fluid in a given circuit. Having information about the flow rate and the resistance of the system, and applying the parameters from the manufacturer’s instructions, we can choose a suitable unit.

Underfloor heating pipe and how to calculate how much you need

What type of pump to choose

After calculating the technical indicators of the unit, necessary for the circulation in the system to be correct, you need to determine the type of pump. For domestic application two types of units are used:

Units with wet rotor have a small capacity, but it is enough to ensure the efficiency of the underfloor heating system does not exceed the area of 400 m2. The rotor is called a wet because of the impeller, located directly in the coolant. It provides lubrication and cooling to the motor. Such devices have advantages due to:

  • quiet operation;
  • low energy consumption;
  • reliability (have a power reserve);
  • Easy operation (does not require additional maintenance).

The circulation pump for underfloor heating with a dry rotor has a high power. The rotor is in an individual sealed housing. In operation, periodic maintenance (lubrication, cleaning) is required. In operation, the unit with a dry rotor behaves quite noisy.

In individual private construction for the arrangement of the system of water underfloor heating almost always stop at the pump variant with a wet rotor.

Casing material and marking

Choosing a circulating pump for underfloor heating, you need to pay attention to the housing material and marking. Usually the material of the body is not important, because with the right choice of pipes and a closed system little oxygen is released. However, in order to protect against oxidation processes, it is better to choose a stainless steel or plastic housing.

The marking applied to the pump body consists of 2-3 digits, such as 25/60-130 or 32/80. The first indicator is the diameters of inlet/outlet holes in millimeters, in the example of 25mm and 32mm. The second indicator is the lift height provided by the unit. In our case, 6m, 8m. When translating meters to atmospheres we get 0.6 and 0.8 atm. The third indicator is the size of the device, its installation length. In the example this figure is 130 mm.



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