What kind of pump is needed for underfloor heating

Features of installation

The pump is mounted between the three-way valve and the system manifold. Only then will the entire structure work. If you install the equipment between the connection to the radiator network and the valve, the mixing unit will not be multifunctional, and the heating will be ineffective.

Attach the appliance to the flanges with coupling nuts. these are supplied in the box. Installation is usually not difficult if the supply line is properly arranged, with sufficient spacing.

How to choose?

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

  • Purchase of the pump should be made simultaneously with all the structural elements of the future system. Thus it will be possible to achieve maximum efficiency of the system and to ensure its longevity. Repair work will be expensive, so it is better to protect yourself.
  • The choice of pump should be based on the capacity of the unit. This parameter can show the capacity in liters or cubic meters. It all depends on the amount of coolant that will be in the system. Multiply this value by 3 and you get the necessary capacity of the pump.
kind, pump, underfloor, heating
  • The head must be chosen according to the parameters of the pipes that make up the system (considering diameter, length, material).
  • A small pump is easier to place in the room, but the size of the unit is directly related to its power. Small pump. limited capacity.
  • Phase also affects the choice of pump. Usually single-phase units are chosen for private objects. But the industrial areas require the installation of pumps with a three-phase motor.
  • Foreign pumps are not always better than domestic analogues. Products of our manufacturers are designed for low water quality and peculiarities of use, typical for our area.

Do you need a pump for underfloor heating?

The peculiarity of the heating system “warm floors” is the use of pipes of small diameter. When laying the loop allowed a lot of bends, which affects the smooth circulation of the fluid. Heating coolant is limited to a temperature of 40 ° C.

All these factors affect the operation and efficiency of heating. As a result, any violation leads to failure of the water circuit, the appearance of air s. Therefore, a water underfloor heating without a pump, it is a wrong decision, although some owners resort to it, trying to save money on components.

Installed circulation pump allows you to create the necessary pressure in the heating system, to ensure the circulation of the coolant. Installing a pump in the system of underfloor heating provides a solution to the most common problems associated with the operation of the heating system. But this becomes possible only with the proper selection of circulation equipment.

How to calculate the parameters of the pump?

Underfloor heating requires not just a simple, but a circulating pump. Not only does it not create excess pressure, but it is also able to push water at the right speed.

The heating of the room in the house varies depending on the season and weather outside, so the speed of movement of the heated heat carrier (water) through the pipes of the warm floor also varies. Experts recommend the optimal variant of the pump. three-speed.

Calculation of the pump in the warm floor is carried out taking into account the two main factors:

Determining the output of the pump in the underfloor heating system

Performance can be calculated by a special formula, substituting the values of water temperatures in the forward and return flow, as well as the power of the circuit itself. If there is more than one circuit, the flow of each circuit is calculated and added to the others.

The total flow rate will be the number of the required pump capacity. Calculation formulas and Комментарии и мнения владельцев from professionals are freely available on the Internet.

A pump can be selected from special tables, which show the meterage of typical houses and radiator heating coefficients. Usually a 20% reserve is put in place in case of poor insulation of the house and the onset of severe winter.

  • If the heating area is up to 120 sqm, the radiator output is 0,5 kW. m the radiator heating performance is 0.4 and the floor heating performance is 1.5;
  • If the heating area is up to 200 sq m, the performance of the radiator heating is 0,4 and that of underfloor heating is 1,5. The radiator heating capacity is 0.6 and the floor heating capacity is 2.5;
  • With a heating area of up to 280 sqm, the heat output of a radiator circuit will be calculated according to a formula. m capacity of the radiator heating 0.8, and the floor heating. 4.

Calculation of the head created by the pump

The head generation is necessary so that the heat carrier can overcome the resistance of the system components. fittings, pipes etc. The total resistance of the system varies in each case depending on the used materials and pipe diameters.

Containment values are given in manufacturer’s literature. At the valve the resistance is taken as 1.7, and at the fitting as 1.2. For the mixer (in case of a high-temperature boiler installation) the coefficient is taken as 1.3.

The head is calculated as a set of the pipe resistance (according to the documentation) and the length of the whole circuit. The value in kilopascals is translated as 100 kPa=0,1 atm (the head is measured in atmospheres).

The resulting number is multiplied by the resistance coefficients of the fittings and various fittings installed in the circuit. After determining the operating point of the pump, you can proceed to the selection of its model. this value should be in the middle of the range of its parameters.

Information on the pump casing

The standard marking on the housing must contain all the technical parameters of the unit. The first number at the top indicates the mounting diameter of the coolant pipe, the second number refers to the pressure (indicating the maximum height at which the fluid can be lifted), and the third number refers to the. the length of the pump in operating condition.

The following indicators show the mains voltage and frequency. Then comes the information about the value of the phase displacement coefficient. On the body there may be information about the height of the fluid lift, depending on the cross-section of the pipes.

Some of the units are equipped with two motors. This design feature allows peak loads to be overcome without allowing the windings to overheat. The second of them, which is also capable of replacing the failed first motor, is put into operation. This eliminates the possibility of sizing in extreme cold.

How to choose a pump for underfloor heating

It is advisable to consider several criteria:

  • Technical characteristics (it is necessary to make preliminary calculations according to the formulas described above and determine a suitable model).
  • Material of the pump casing. preferably cast iron, stainless steel or organic polymers. These materials last the longest due to their high anti-corrosion properties.
  • Availability of built-in thermostat allows you to protect the impeller from limescale and deposits, which are formed due to exposure to hot water.
  • The brand. the most reliable are Germany (Wilo) and Denmark (Grundofs). Budgetary variants with optimal price/quality ratio are Poland (DAB) and China (Sprut). Also popular are Italian manufacturers (Lowara, Pedrollo) and Japanese brand Ebara.
  • The speed of the floor pump. usually models work at 3 speeds, which is especially convenient for a large heating area, as well as 2-3-storey houses.

What information is printed on the pump casing

The standard designation should state all the technical specifications of the pump. The first upper digit on the pump indicates the installation diameter of the water pipes, the second the maximum lifting height of the liquid (pressure), and the third the overall length of the unit in the operating position. The following figures indicate the operating voltage and frequency of oscillation in the network, the coefficient of phase offset. As additional information, the change of the maximum lifting height of water depending on the diameter of the pipelines can be given.

Some pumps have two motors each, which allows peak loads to be passed without overheating of the windings due to automatic activation of the second motor. In addition, the second motor serves as an additional protection for the heating system in the event that one of the motors should fail. This protection prevents the system from sagging in wintertime.

Pump for underfloor heating: types and selection rules

Underfloor heating has long ceased to be a unique phenomenon, today it is available to everyone, in the presence of the necessary literature and acquired knowledge to install it yourself without attracting professionals. This system is gaining popularity: it is now mounted not only in private houses, but also in apartments. Underfloor heating systems are cost-effective in operation, but expensive to install. Therefore, it is necessary to correctly select all components, one of which is a water pump.

ProWarm underfloor heating. pumps and manifolds installation

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

Installation Features

Wherever you put a circulating pump, its rotor must be directed horizontally. In principle, vertical installation is possible, but then the choice must be taken into account that in this case it will lose about 30% of the power.

At installation in system of a water floor the pump more often is put in a supply pipeline, but already after a mixing knot (here the temperature will be normal for it). Although there are schemes in which it is installed in the “return” or bypass. Some schemes have two pumps. It is recommended to install two independent devices in a two-storey house: one on each level. It is easier to regulate the pressure in each of the branches.

Circulation pumps are often installed in the supply line after the pump group

kind, pump, underfloor, heating

There will definitely be air in the system when you fill it up. Its presence can block the movement of the coolant: an air lock is formed. Not all manifolds have the ability to bleed. That’s why many pumps have a special outlet valve. This is a small disk on the front panel, which has a groove. In the groove you rest the screwdriver and slightly turn the disc counterclockwise. The air starts to come out (put some kind of utensil underneath, because gradually with the air bubbles, water will start to come out). When the water flows in a continuous stream without bubbles, close the valve, restart the system and try again to bleed. Sometimes you have to repeat the procedure several times before all the air is purged.

There is another peculiarity of water underfloor heating systems. If you do not use low-temperature sources (condensing gas or electric boilers), then before you supply water to the floor pipes, the hot water from the boiler is mixed with chilled water from the “return”. Everything, of course, can be assembled from individual elements, but you can also buy a pump and mixing unit (or pump group) in the assembly. They come in different compositions, and therefore prices, but they perform a basic function: to maintain the water temperature you set at the inlet to the manifold node. But the basis of this group of devices is still the same pump, and you need to choose it according to the parameters that we calculated above.

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