Do you need a pump for underfloor heating?

How to choose a pump for underfloor heating

It is recommended to consider several criteria:

  • Technical characteristics (it is necessary to make preliminary calculations according to the formulas described above and determine a suitable model).
  • The material of the pump body. preferably cast iron, stainless steel or organic polymers. These are the materials that 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 that are formed due to exposure to hot water.
  • Brand. Germany (Wilo) and Denmark (Grundofs) are the most reliable brands. Budgetary options with an optimal price/quality ratio are Poland (DAB) and China (Sprut). Also popular are Italian manufacturers (Lowara, Pedrollo) and Japanese brand Ebara.
  • Floor pump speed mode. usually models operate at 3 speeds, which is especially convenient for a large heating area, as well as 2-3-story houses.

Pump for water underfloor heating. what to choose, how to make a calculation of performance and install with your own hands

Water underfloor heating. a complex structure, consisting of many components. One such element is the circulation pump, it determines how effectively the floor will work.

Today we will tell you what are the types of pumps, and what they have characteristics. You will learn how to select and calculate the capacity of the circulation pump for underfloor heating, and how to install the heating with it.

What pump is needed for underfloor heating

For a house with a typical area (up to 250-300 m 2 ) and 1-2 floors, you can choose a pump equipped with a wet-type rotor, the impeller of which is submerged in water. This provides low noise and durability (no need to constantly lubricate the mechanism). If the house has a larger area or more than 2 floors, it is better to consider a model with a dry rotor. Therefore, it is necessary to clarify exactly how they differ:

  • Wet rotor. these are appliances with medium power, they are optimally suited for premises up to 250-350 m 2. The impeller of the mechanism is directly in the water. The equipment works quite quietly, while it consumes little energy and serves a long time.
  • Dry rotor. particularly powerful options. Applicable on surfaces with an area of 250 m 2 and more. Need to be cleaned and lubricated. If the house has 3 or more floors, you should also consider a dry rotor.

need, pump, underfloor, heating

Wet rotor pumps are suitable for standard houses with a medium area

How to install a pump for underfloor heating

Once the location has been selected, proceed to installation. The algorithm of action is as follows:

  • First, a bypass. a bypass pipe is installed in the place to be mounted.
  • To do this, it is necessary to cut the main pipe.
  • Form a thread on its ends.
  • Put a ball valve and install a pump.
  • Open the tap for water access.
  • Open the screw for bleeding air.
  • After installing the circulating pump to the floor heating must always test the system. First of all check the work at a low speed.

Diagram for the correct installation of a floor heating pump

How to calculate the capacity of a floor heating pump

You can estimate this parameter by the basic technical characteristics, which are denoted by 2 digits, for example: 25/40. The first figure indicates the thread diameter, in this case 25 mm, and the second figure the head: 40 dm or 4 m (i.e. 0.4 atm). The choice depends on the floor area.

The following formula can be used to accurately calculate the head:

Important! If the area of the house more than 250 m2, you can install 2 devices with a head of 25/40, to take “with a reserve”, that is, with a greater head, should not be, because it is impractical. Heating will be about the same, but the noise and energy costs will increase noticeably.

Capacity is determined by the volume of water passed per unit time (m3 per hour). Selection of a suitable pump for underfloor heating can be made with the help of the table.

Accurate calculation of the main characteristic of the pump for the underfloor heating can be made on the basis of this equality:

  • Q. capacity;
  • P. power of the appliance;
  • t1. temperature of water or other medium in return pipe;
  • t2. temperature of water or other medium in the supply pipe.

For houses with a larger area, the same principle works. it is better to install 2 pumps with average performance, than 1 device with a large capacity. In this case, you will need to calculate the index of each device, and then sum up the obtained values.

It is better to buy sufficiently productive pumps for the floor (15-20% more than calculated). this will help in case of abnormally cold winters or weak insulation of the house

Pressure and capacity

The required characteristics of the pump and its brand should be determined in the project for the floor heating based on the heat loss, area, number of loops, pipe brand, pipe diameter, loop length, temperature difference.

Heat pump and underfloor heating in residential market (VF, VEng)

But acquiring a project, or even performing simple calculations, for many is not a desirable expenditure of time, money and effort.

ProWarm underfloor heating. pumps and manifolds installation

The choice is only between 25/40 and 25/60 (for large areas is better to put two or more “small” pump and mixing nodes). other suitable options are simply difficult to find.

If you take a radiator system, its simplicity simplifies the choice of pump group. Up to a house area of up to 160 square meters. will do 25/40. In the range of 160. 250. m sqm 25/60 and t.д.

“Child’s disease of home installers”. to install circulation pumps “with a reserve just in case”. Where 20 is enough, put 80. get a very significant overrun of electricity, noise in the radiators and pipes.

With the choice of a pump for underfloor heating is almost as simple. Although there is more diversity in the input data. the length of the circuits can vary substantially from 20 m to 140 m, requests for differential temperature of supply and return can be different, more influence the thermal insulation of the floor, etc.

To minimize the temperature difference between supply and return, you need to install a more productive pump.

Selection of a heat exchanger for connection to the CHP unit

In order to choose the right heat exchanger to connect the water floor heating to the central heating, you need to determine the degree of contamination of the coolant to understand how much water needs to be cleaned. If the scale is small, a coarse filter that retains swarf and scale will be sufficient. Such a filter can be cleaned with special agents, if after some time it gets dirty and requires cleaning.

Each heat exchanger necessarily has information about the type of product, the company-manufacturer, specifies the maximum and test pressure, the maximum operating temperature, the scheme of location of attachment, necessarily designation of circuits, which can be arranged both diagonally and vertically. A special arrow shows the direction of installation of the product, that is, in what position it should be installed. It is important to understand how the outflow of heat transfer fluids. The circulation itself is carried out by the so-called circulation pump.

On the diagram in the passport you can usually find how to perform the installation correctly. For example, one of the options is to press the product to the wall with a fixing tape or console and, using a special angle, screw it on. Filters are mandatory for installation, you need at least a coarse filter.

Marking and body material

These are two or three digits like: 25/40, 25/60-130 or 32/80, etc.п. The first number is the diameter of inlets/outlets in millimeters. That is, in the given marking, the connection dimensions are 25 mm and 32 mm. The second number is the height of elevation provided by the model. In the example given is 4 meters, 6 meters and 8 meters. If you translate atmospheres, it is 0.4 atm, 0.6 atm, 0.8 atm. The third figure is the installation length, that is, the size of the entire unit from one end to the other. In our example it is 130 mm.


Deciphering the marking of circulating pumps

Now let’s decide on the material of the body. If the pipes are chosen correctly, there should be no problems: the system is closed and there is little oxygen, so it will be possible to put a unit of any material. But if you have not considered oxygen permeability and this active oxidant is present in the system, then the cast iron body of your system is contraindicated. Then put with a corpus of stainless steel or polymer.

As for the companies. It is best to take the equipment of European manufacturers. When choosing a pump for a water heated floor it is better not to save: on how stable this element works, depends on your comfort and the presence of heat in the house. Choose the best firms, with the best reputation. Well-proven German companies Grundfos and Wilo. But in the case of Wilo, you need to look at the country for which the product is made: those that go to the market of the CIS and China are more likely to fail. So be careful.

Starting water underfloor heating

Water heated floor. a multilayer device. Therefore, even the process of commissioning, which seems simple, has its own peculiarities. Before you begin installing the structure, you need to understand how to properly fill and turn on a warm water floor, and you need to read the instructions for use.

The first start-up includes: filling, flushing, draining, adjusting the system, heating and drying the screed. The principle of operation depends on the used coolant and type of heating, it is closed and open. In addition, an important point when starting the floor is to ensure the circulation of the liquid and the removal of air s from the circuit.

In order to properly start the device. a water heated floor, the output manifold must have a special faucet. The compression apparatus necessary for checking the floor can be rented.

But if the pipeline pumped water, not antifreeze, it is better to have your own device. You will have to use the device often, as it is recommended to replace the coolant annually, and therefore conduct testing of the system.

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