Calculation of a pump for a well is one of the main conditions, if met, which can guarantee long-term and uninterrupted use of the well on the site. By calculating a well pump, you will be able to correlate your water needs with the conditions in which the pumping equipment will be operated. Only based on the calculation results can you purchase the optimal pump model for a well, which will not only satisfy all needs, but will also last for many years.

Before proceeding directly to the calculations, it is necessary to analyze in detail all the fundamental factors for choosing a well pump. And the first thing we start with is the source of water itself.

As you know, you can drill a well either yourself or using the services of specialists. In this article, as an example, we will simulate the situation with the second option, namely with a finished well from a specialized organization. In this case, you already have a well passport with detailed characteristics of the object. And the first parameter that should interest us is casing outer diameter. Today, wells are often found whose diameter varies from 100 to 150 millimeters. You need to know the exact diameter of the well pipe, because this indicator will allow you to determine the transverse size of the future pump.

Important When selecting a well pump according to parameters, remember that between the pump body and the walls of the well there must be a gap of 1 to 3 centimeters, depending on the model. Neglecting this recommendation will lead to failure of the pumping equipment long before the end of the warranty period. But don’t rush to rejoice - no one will just change such a pump, because the user has not provided the recommended operating conditions, which completely voids all warranty obligations from the manufacturer.

The next important characteristic of a well is its productivity or flow rate. The flow rate is the maximum amount of water that a well can produce per unit of time. Accordingly, the greater the flow rate of the source, the more productive the pump can be installed.

The flow rate itself has two important meanings - static and dynamic liquid level. The static indicator displays the water level in the well when liquid is not pumped out. The dynamic level determines the amount of water in the source during pump operation.

If the dynamic level remains unchanged during water pumping, then we can safely say that the productivity of the well is equal to the productivity of the selected pump. If the difference between the static and dynamic levels is less than one meter, then the water source being developed has high productivity, which exceeds the characteristics of the installed pumping equipment. But if an error is made when calculating the power of a well pump, and the productivity of the selected pump exceeds the flow rate of the well, then the dynamic level of the liquid will gradually decrease until the water runs out completely. As a result of such a miscalculation, the pump will run dry, which will have a detrimental effect on its service life. Moreover, all submersible well pumps have a special monoblock design, where the electric motor is cooled by the pumped liquid, and if there is a lack of water in the well, the electric motor will quickly heat up and burn out.

Calculation of pump performance for a well

When calculating the performance of a pump for a well, it is also worth taking into account the natural fluctuations of the fluid, which for one reason or another can affect the water level in the well. As practice shows, during the year, under the influence of such meteorological factors as drought, heavy rainfall and floods, the liquid level can increase or, on the contrary, decrease from 1 to 5-6 meters, depending on the intensity of the above phenomena. Pumps in such wells must be installed several meters deeper than the minimum possible dynamic liquid level. Thus, it is possible to additionally insure downhole equipment in case of possible shallowing of the source.

Having analyzed the main characteristics of the well, you can begin to select the desired pump model. Here we will be interested in the operational parameters of the equipment, namely:

• Performance- this is the ability of a well pump to pump a certain volume of water in a set period of time.

  Note: To determine the required volume of liquid, you can use the average value, where one person consumes approximately 1000 liters of water or one cubic meter per day. But do not forget that, as a rule, in a country house there are several water points. These can be taps, mixers, washing machines and dishwashers, bathtubs, shower rooms. And there is always the possibility of their one-time use. Of course, not all at once (although this possibility also exists), but several, that’s for sure. In general, we need the pump, in addition to the average flow, to cope with possible peak load.

• Pressure, without going into details, the pressure of a well pump is an indicator of the pressure created that a particular pump can provide when pumping a certain amount of liquid. If you are wondering what pressure is required, then this means how much pressure the pump needs to provide in order to pump a certain volume of liquid from the initial suction point to the final water distribution point, while overcoming all the hydraulic resistance of the plumbing system.

Calculation of well pump pressure

The pressure is calculated using the following formula:

Pressure = (distance from the pump installation point in the well to the ground surface + horizontal distance from the well to the nearest water point * + height of the highest water point in the house) × water resistance coefficient **

If the well pump will be operated together with a storage tank, then the pressure value in the storage tank must be added to the above formula for calculating the pressure:

Pressure = (distance from the pump installation point in the well to the ground surface + horizontal distance from the well to the nearest water point + height of the highest water point in the house + pressure in the storage tank ***) × water resistance coefficient

Note * - when calculating, keep in mind that 1 vertical meter equals 10 horizontal ones;
** - water resistance coefficient is always equal to 1.15;
*** - each atmosphere is equivalent to 10 vertical meters.

Everyday mathematics For clarity, let’s simulate a situation in which a family of four needs to select a pump for a well 80 meters deep. The dynamic level of the source does not fall below 62 meters, that is, the pump will be installed at a depth of 60 meters. The distance from the well to the house is 80 meters. The height of the highest point of water intake is 7 meters. The water supply system has a storage tank with a capacity of 300 liters, that is, for the entire system to function, a pressure of 3.5 atmospheres must be created inside the accumulator. We count:

Head=(60+80/10+3.5×10)×1.15=126.5 meters.

What pump is needed for the well in this case? – an excellent option would be to purchase Grundfos SQ 3-105, the maximum pressure value of which is 147 meters, with a productivity of 4.4 m³/h.

In this material, we examined in detail how to calculate a pump for a well. We hope that after reading this article you will be able to calculate and select a well pump without outside help, which, thanks to a competent approach, will last for many years.

To organize water supply for a private home, before installing pumping equipment, it is first necessary to calculate its parameters. In this case, it is necessary to take into account the technical characteristics of the source, the distance to the consumer and the volume of water intake. A homeowner who independently installs a water supply line into a house does not need to calculate a pump for a well using complex formulas - online calculators posted on the Internet are designed for this.

Rice. 1 Online calculator for determining the supply volume - appearance

Their significant drawback is the approximate nature of the results obtained - many important parameters that influence the final result do not appear in the input data. Almost all online calculators calculate only one of the parameters: lift height, productivity or required pressure in the line; the remaining data must be determined in other ways. Another problem is choosing an accurate and reliable calculator from the many options available online. Therefore, the most correct solution to the question of how to calculate a pump for a well remains to calculate its parameters using formulas using loss tables and using calculators as an aid to check the correctness of the calculations.

Rice. 2 Online calculator for calculating a water supply pump

The need to accurately determine the parameters of pumping equipment is very important when ensuring a constant water supply to a private home. If the performance is calculated inaccurately, the water intake devices will pump out an insufficient amount of water - this will require its replacement and, accordingly, additional costs. The use of pumping equipment with a large margin of parameters can lead to even greater financial losses: in addition to unjustified expenses upon purchase, during operation the electric pump will operate with low efficiency, consuming an unreasonably large amount of electricity.

Rice. 3 Connection diagram for a submersible well pump

When calculating an electric water pump for a water supply system, it is necessary to take into account the following parameters of the water intake tank and water main.

Depth of water source

It is necessary to know the depth of a borehole or well bottom when determining the flow rate of a source; this is important from a practical point of view - the found distance from the surface to the bottom will allow you to optimally select a pump with the required immersion depth and lift height in this range.

Rice. 4 Static and dynamic levels

Static level

The distance from the source water surface to the surface plays a role in determining the lift height and immersion depth of the pump. The static level is determined when there is no water intake and the source is in a calm state for at least an hour or, for higher accuracy, a day. The indicator has a seasonal dependence and falls during spring floods, so its highest level should be determined in dry summer weather.

Dynamic level

The distance from the water mirror to the surface when the electric pump is running is a dynamic level; it differs significantly from the static level in shallow, low-yield Abyssinian or sand wells with low pressure. In artesian springs, where the water pressure is significantly higher and is balanced by a high column, the dynamic level for domestic intake volumes is usually equal to the static level.

Knowing the dynamic level is especially important when selecting the immersion depth of an electric pump - when turned off, it will experience a load from a column of liquid with a height from the immersion depth under the dynamic level mirror (1 - 2 m) to the surface of the static level.

Consumption volume

The calculation of pump performance depends on the number of people living and connected points and is calculated using water intake calculators for household appliances and plumbing fixtures. It should be taken into account that consumption should not exceed the flow rate of the source.

Fig.5 Table of water consumption for household plumbing

Diameter of well pipes or well

This indicator mainly affects the choice of pump model. In narrow, shallow Abyssinian wells it is impossible to install a deep submersible electric pump; the liquid is lifted by centrifugal surface units and lowered into the source by a suction water intake pipe. Standard submersible well centrifugal electric pumps have a diameter of about 4 inches and are designed to be immersed in boreholes with a diameter of at least 100 mm. Some high-performance submersible models with a diameter of 6 inches require well pipes with a width of at least 150 mm. Well rings must be wide enough to install a well electric pump with a surface float switch located on the water surface up to 300 mm. from the central axis of the pump.

Water quality

The liquid that the electric pump lifts to the surface has different quality depending on the type of water intake source. In budget Abyssinian species with a depth of no more than 8 m, due to their low weight and design features, the suction holes are located in the thickness of the aquifer. The well produces clean water; centrifugal or vortex types of electric pumps can be used to collect it. Due to their significant mass, deeper sand wells are located on the sandy or clay bottom of the aquifer. Depending on the structure of the bottom, pressure, and the distance of the inlet of the pressure pipe, the lifted liquid in sand wells has varying degrees of purity. To draw clean water from sources or with a low content of impurities, deep centrifugal electric pumps are used; more turbid liquid can be lifted using screw-type devices. Vibrating models, due to their harmful effects on the walls of casing pipes, low productivity, short continuous suction time and low efficiency, are not used to ensure constant water supply to a private home. When calculating pump power, the calculator must take into account hydraulic losses in water filters.

The casing pipes of artesian wells are installed on a solid limestone bottom; the water raised in this case is the cleanest with a very high iron content; vortex or centrifugal electric pumps can be used for intake.

Distance from home to source

When calculating the required pressure, vertical meters are converted to horizontal; this ratio depends on the diameter and material of the pipeline, which affect its hydraulic resistance.

Water pressure

The electric pump must not only deliver water to the consumer, but also provide the necessary pressure in the system. This indicator affects the strength of the water stream in the tap, and ensures the operation of automation configured to a certain range. First of all, this applies to the pressure and idle speed switches; at low pressure, the automation will not turn off the electric pump; its excessive value, in addition to everyday inconveniences, can lead to rapid failure of the components of the water supply system.

Calculation of the main parameters of the water supply system

Rice. 6 Losses in the water supply system depending on the diameter of the pipes

When choosing and calculating an electric well pump for a water supply system, it is necessary, taking into account the above data, to correctly select its following parameters.

Type of electric pump based on its operating principle. As mentioned above, the well pump is selected according to the operating principle individually for each type of water intake tank.

Immersion depth. The value in the pump data sheet should not be lower than the difference between the dynamic and static levels.

Feed volume. Calculation of productivity is carried out taking into account the number of people living in the house, household appliances consuming water (washing machines and dishwashers) and points of collection. Showers and bathtubs, toilets, bidets, sinks and sinks are taken into account.

It is often necessary to care for plants on the site, so the water supply must take into account the cost of irrigation. You can calculate the power and supply volume using tables or by making calculations with a calculator, summing up all the indicators.

It is not at all necessary to count all the water intake points in the house in order to determine the power of the pump; you can use the tables to determine the consumption according to daily norms, the average figure being within 200 liters. for one person.

Rice. 7 Daily consumption rates

Lifting height. The main parameter of the pump, which must be accurately calculated. The pressure indicated in the passport data must perform the following functions:

• Lifting liquid from a water intake tank to a height to the surface from a distance of 1 - 2 m below the dynamic level.
• Horizontal supply to the consumer. When calculating, take 1 m of vertical column equal to 10 m of horizontal plastic pipes with a diameter of 1 inch. When the pipe diameter is reduced, the flow rate drops significantly; pipes of smaller diameter are rarely used in the water supply system. It is also unprofitable to use steel pipes, the hydraulic resistance of which is greater than plastic ones and the flow rate is reduced by 0.7 times.
• Operating pressure. The pump must provide pressure for the system to operate, the standard values ​​of which are 1.4 - 2.8 bar. (1 bar is approximately equal to 1 atm or 10 m of vertical water column).

Rice. 8 Table of hydraulic losses

Htr is the desired value for a deep-well pump.

H geo – the height of the rise and the length of the horizontal section in vertical meters of water column.

H losses – the amount of losses in the water supply system, determined using tables or calculations. These losses are associated with friction of the liquid on the surface of the pipes, as well as a drop in speed in elbows and tees.

H free – pressure to create working pressure in the system. This value must be taken in the range of 15 – 30 m.

Calculation of productivity and lift height is the main task when choosing pumping equipment. The first parameter can be set according to consumption standards per person; when calculating the pressure, the length of the vertical section, the length of the horizontal line and the pressure in the system, converted to meters of water column, are summed up. In this case, power calculation will not be needed; it will depend on the performance of the submersible electric pump and the height of the liquid.

When arranging water supply and heating for country houses and dachas, one of the most pressing problems is the selection of a pump. A mistake in choosing a pump is fraught with unpleasant consequences, among which excessive energy consumption is the simplest, and failure of a submersible pump is the most common. The most important characteristics by which any pump must be selected are water flow or pump performance, as well as pump pressure or the height to which the pump can supply water. A pump is not an equipment that can be taken with a reserve - “for growth”. Everything must be adjusted strictly according to needs. Those who were too lazy to make the appropriate calculations and chose the pump “by eye” almost always have problems in the form of failures. In this article we will dwell in detail on how to determine pump pressure and performance and provide all the necessary formulas and tabular data. We will also clarify the subtleties of calculations of circulation pumps and the characteristics of centrifugal pumps.

How to determine the flow and pressure of a submersible pump

Submersible pumps are usually installed in deep wells and wells, where a self-priming surface pump cannot cope. Such a pump is characterized by the fact that it operates completely immersed in water, and if the water level drops to a critical level, it turns off and will not turn on until the water level rises. Running a submersible pump “dry” without water is fraught with breakdowns, so it is necessary to select a pump with such a performance that it does not exceed the flow rate of the well.

Calculation of performance/flow rate of a submersible pump

It is not for nothing that pump performance is sometimes called flow rate, since calculations of this parameter are directly related to water flow in the water supply system. In order for the pump to be able to meet the water needs of residents, its performance must be equal to or slightly greater than the water flow from simultaneously switched on consumers in the house.

This total consumption can be determined by adding up the expenses of all water consumers in the house. In order not to bother yourself with unnecessary calculations, you can use the table of approximate values ​​of water consumption per second. The table shows all kinds of consumers, such as washbasin, toilet, sink, washing machine and others, as well as the water consumption in l/s through them.

Table 1. Consumption of water consumers.

After summing up the costs of all required consumers, it is necessary to find the estimated flow rate of the system; it will be somewhat less, since the likelihood of using absolutely all plumbing fixtures at the same time is extremely low. You can find out the estimated flow rate from Table 2. Although sometimes, to simplify the calculations, the resulting total flow rate is simply multiplied by a factor of 0.6 - 0.8, assuming that only 60 - 80% of plumbing fixtures will be used at the same time. But this method is not entirely successful. For example, in a large mansion with many plumbing fixtures and water consumers, only 2 - 3 people can live, and the water consumption will be much less than the total. Therefore, we strongly recommend using the table.

Table 2. Estimated flow rate of the water supply system.

The result obtained will be the actual consumption of the house’s water supply system, which must be covered by the pump’s performance. But since in the pump characteristics the performance is usually calculated not in l/s, but in m3/h, the flow rate we obtained must be multiplied by a factor of 3.6.

Example of calculating the flow rate of a submersible pump:

Let's consider the option of water supply for a country house that has the following plumbing fixtures:

• Shower with mixer - 0.09 l/s;
• Electric water heater - 0.1 l/s;
• Sink in the kitchen - 0.15 l/s;
• Washbasin - 0.09 l/s;
• Toilet - 0.1 l/s.

Let's sum up the consumption of all consumers: 0.09+0.1+0.15+0.09+0.1=0.53 l/s.

Since we have a house with a garden plot and a vegetable garden, it wouldn’t hurt to add a watering tap here, the flow rate of which is 0.3 m/s. Total, 0.53+0.3=0.83 l/s.

We find the value of the calculated flow rate from Table 2: the value of 0.83 l/s corresponds to 0.48 l/s.

And lastly, we convert l/s to m3/h, for this 0.48*3.6=1.728 m3/h.

Important! Sometimes the pump capacity is indicated in l/h, then the resulting value in l/s must be multiplied by 3600. For example, 0.48*3600=1728 l/h.

Conclusion: the flow rate of the water supply system of our country house is 1.728 m3/h, so the pump capacity must be greater than 1.7 m3/h. For example, the following pumps are suitable: 32 AQUARIUS NVP-0.32-32U (1.8 m3/h), 63 AQUARIUS NVP-0.32-63U (1.8 m3/h), 25 SPRUT 90QJD 109-0.37 (2 m3 /h), 80 AQUATICA 96 (80 m) (2 m3/h), 45 PEDROLLO 4SR 2m/7 (2 m3/h), etc. To more accurately determine the appropriate pump model, it is necessary to calculate the required pressure.

Calculation of submersible pump pressure

The pump pressure or height of water rise is calculated using the formula presented below. It is taken into account that the pump is completely immersed in water, so parameters such as the height difference between the water source and the pump are not taken into account.

Calculation of well pump pressure

Formula for calculating the pressure of a well pump:

Htr- the value of the required pressure of the well pump;

Hgeo- height difference between the location of the pump and the highest point of the water supply system;

Hloss- the sum of all losses in the pipeline. These losses are associated with friction of water on the pipe material, as well as pressure drop at pipe bends and tees. Determined from the loss table.

Free- free pressure on the spout. In order to be able to comfortably use plumbing fixtures, this value must be taken at 15 - 20 m, the minimum acceptable value is 5 m, but then the water will be supplied in a thin trickle.

All parameters are measured in the same units in which pump pressure is measured - in meters.

The pipeline loss calculation can be calculated by examining the table below. Please note that in the table of losses, the speed at which water flows through a pipeline of the corresponding diameter is indicated in regular font, and in highlighted font, the pressure loss for every 100 m of a straight horizontal pipeline. At the very bottom of the tables, losses in tees, corner joints, check valves and gate valves are indicated. Naturally, to accurately calculate losses, it is necessary to know the length of all sections of the pipeline, the number of all tees, turns and valves.

Table 3. Pressure loss in a pipeline made of polymer materials.

Table 4. Pressure loss in a pipeline made of steel pipes.

An example of calculating the pressure of a well pump:

Let's consider this option for water supply to a country house:

• Well depth 35 m;
• The static water level in the well is 10 m;
• The dynamic water level in the well is 15 m;
• Well flow - 4 m3/hour;
• The well is located at a distance from the house - 30 m;
• The house is two-story, the bathroom is on the second floor - 5 m high;

First of all, we consider Hgeo = dynamic level + height of the second floor = 15 + 5 = 20 m.

Next we calculate Hloss. Let us assume that our horizontal pipeline is made with a 32 mm polypropylene pipe to the house, and in the house with a 25 mm pipe. There is one corner rotation, 3 check valves, 2 tees and 1 shut-off valve. Let's take the productivity from the previous flow calculation as 1.728 m3/hour. According to the proposed tables, the closest value is 1.8 m3/hour, so let’s round up to this value.

Hloss = 4.6*30/100 + 13*5/100 + 1.2 + 3*5.0 + 2*5.0 + 1.2 = 1.38+0.65+1.2+15+ 10+1.2=29.43 m ≈ 30 m.

Let's take 20 m as free.

In total, the required pump pressure is:

Htr = 20 + 30 + 20 = 70 m.

Conclusion: taking into account all the losses in the pipeline, we need a pump whose pressure is 70 m. Also, from the previous calculation, we determined that its productivity should be higher than 1.728 m3/hour. The following pumps are suitable for us:

• 80 AQUATICA 96 (80 m) 1.1 kW - capacity 2 m3/hour, head 80 m.
• 70 PEDROLLO 4BLOCKm 2/10 - capacity 2 m3/hour, head 70 m.
• 90 PEDROLLO 4BLOCKm 2/13 - capacity 2 m3/hour, head 90 m.
• 90 PEDROLLO 4SR 2m/ 13 - capacity 2 m3/hour, head 88 m.
• 80 SPRUT 90QJD 122-1.1 (80m) - capacity 2 m3/hour, head 80 m.

A more specific choice of pump depends on the financial capabilities of the dacha owner.

Calculation of a membrane tank (hydraulic accumulator) for water supply

The presence of a hydraulic accumulator makes the pump more stable and reliable. In addition, this allows the pump to turn on less often to pump water. And another advantage of the hydraulic accumulator is that it protects the system from hydraulic shocks, which are inevitable if the pump is powerful.

The volume of the membrane tank (hydraulic accumulator) is calculated using the following formula:

V- tank volume in l.

Q- nominal flow/performance of the pump (or maximum performance minus 40%).

ΔP- the difference between the pressure indicators for switching on and switching off the pump. The switching pressure is equal to - maximum pressure minus 10%. The shutdown pressure is equal to the minimum pressure plus 10%.

Pon- switching pressure.

nmax- the maximum number of pump starts per hour, usually 100.

k- coefficient equal to 0.9.

To make these calculations, you need to know the pressure in the system - the pump activation pressure. A hydraulic accumulator is an irreplaceable thing, which is why all pumping stations are equipped with it. Standard volumes of storage tanks are 30 l, 50 l, 60 l, 80 l, 100 l, 150 l, 200 l and more.

How to calculate the pressure of a surface pump

Self-priming surface pumps are used to supply water from shallow wells and boreholes, as well as open springs and water storage tanks. They are installed directly in a house or technical room, and a pipe is lowered into a well or other water source, through which water is pumped to the pump. Typically, the suction height of such pumps does not exceed 8 - 9 m, but supply water to a height, i.e. the pressure can be 40 m, 60 m or more. It is also possible to pump water from a depth of 20 - 30 m using an ejector that is lowered into the water source. But the greater the depth and distance of the water source from the pump, the more the pump’s performance drops.

Self-priming pump performance is calculated in exactly the same way as for a submersible pump, so we will not focus on this again and will immediately move on to the pressure.

Calculation of the pressure of a pump located below the water source. For example, the water supply tank is located in the attic of the house, and the pump is on the ground floor or in the basement.

Ntr- required pump pressure;

Ngeo- height difference between the pump location and the highest point of the water supply system;

Lost- losses in the pipeline associated with friction. They are calculated in exactly the same way as for a well pump, but the vertical section from the tank, which is located above the pump, to the pump itself is not taken into account.

Nsvob- free pressure from plumbing fixtures, it is also necessary to take 15 - 20 m.

Tank height- height between the water storage tank and the pump.

Calculation of the pressure of a pump located above the water source- well or reservoir, container.

This formula has absolutely the same values ​​as the previous one, only

Source height- height difference between the water source (well, lake, dig, tank, barrel, trench) and the pump.

An example of calculating the pressure of a self-priming surface pump.

Consider this option for water supply to a country house:

• The well is located at a distance of 20 m;
• Well depth - 10 m;
• Water mirror - 4 m;
• The pump pipe is lowered to a depth of 6 m.
• The house is two-story, the bathroom is on the second floor - 5 m high;
• The pump is installed directly next to the well.

We consider Ngeo - height 5 m (from the pump to the plumbing fixtures on the second floor).

Loss - let’s assume that the outer pipeline is made of a 32 mm pipe, and the inner one is 25 mm. The system has 3 check valves, 3 tees, 2 shut-off valves, 2 pipe turns. The pump capacity we need should be 3 m3/h.

Nloss = 4.8*20/100 + 11*5/100 + 3*5 + 3*5 + 2*1.2 + 2*1.2 = 0.96+0.55+15+15+2, 4+2.4=36.31≈37 m.

Nfree = 20 m.

Source height = 6 m.

Total, Ntr = 5 + 37 + 20 + 6 = 68 m.

Conclusion: a pump with a head of 70 m or more is required. As the selection of a pump with such a water supply has shown, there are practically no models of surface pumps that would meet the requirements. It makes sense to consider installing a submersible pump.

How to determine the flow and pressure of a circulation pump

Circulation pumps are used in home heating systems to ensure forced circulation of coolant in the system. Such a pump is also selected based on the required performance and pump pressure. The graph of pressure versus pump performance is its main characteristic. Since there are one-, two-, three-speed pumps, they have one, two, three characteristics, respectively. If the pump has a smoothly varying rotor speed, then there are many such characteristics.

Calculating a circulation pump is a responsible task; it is better to entrust it to those who will carry out the heating system project, since for calculations it is necessary to know the exact heat loss of the house. The selection of a circulation pump is carried out taking into account the volume of coolant that it will have to pump.

Calculation of circulation pump performance

To calculate the performance of the heating circuit circulation pump, you need to know the following parameters:

• Heated area of ​​the building;
• Power of the heat source (boiler, heat pump, etc.).

If we know both the heated area and the power of the heat source, then we can immediately proceed to calculating the pump performance.

Qn- pump flow/performance, m3/hour.

Qnecessary- thermal power of the heat source.

1,16 - specific heat capacity of water, W*hour/kg*°K.

The specific heat capacity of water is 4.196 kJ/(kg °K). Convert Joules to Watts

1 kW/hour = 865 kcal = 3600 kJ;

1 kcal=4.187 kJ. Total 4.196 kJ = 0.001165 kW = 1.16 W.

tg- coolant temperature at the outlet of the heat source, °C.

tх- temperature of the coolant at the inlet to the heat source (return), °C.

This temperature difference Δt = tg - tx depends on the type of heating system.

Δt= 20 °С- for standard heating systems;

Δt = 10 °С- for low-temperature heating systems;

Δt = 5 - 8 °C- for the “warm floor” system.

An example of calculating the performance of a circulation pump.

Let's consider this option for a house heating system: a house with an area of ​​200 m2, a two-pipe heating system, made with a 32 mm pipe, length 50 m. The coolant temperature in the circuit has a cycle of 90/70 ° C. The heat loss of the house is 24 kW.

Conclusion: For a heating system with these parameters, a pump with a flow/performance of more than 2.8 m3/hour is required.

Calculation of circulation pump pressure

It is important to know that the pressure of the circulation pump does not depend on the height of the building, as was described in the examples of calculating a submersible and surface pump for water supply, but on the hydraulic resistance in the heating system.

Ntr- required pressure of the circulation pump, m.

R- losses in the direct pipeline due to friction, Pa/m.

L- total length of the entire heating system pipeline for the farthest element, m.

ρ - density of the flowing medium, if it is water, then the density is 1000 kg/m3.

g- free fall acceleration, 9.8 m/s2.

Z- safety factors for additional pipeline elements:

• Z=1.3- for fittings and fittings.
• Z=1.7- for thermostatic valves.
• Z=1.2- for a mixer or device preventing circulation.

As it was established through experiments, the resistance in a straight pipeline is approximately equal to R = 100 - 150 Pa/m. This corresponds to a pump pressure of approximately 1 - 1.5 cm per meter.

The pipeline branch is determined - the most unfavorable, between the heat source and the most remote point of the system. It is necessary to add the length, width and height of the branch and multiply by two.

L = 2*(a+b+h)

An example of calculating the pressure of a circulation pump. Let's take the data from the example of calculating productivity.

First of all, we calculate the pipeline branch

L = 2*(50+5) = 110 m.

Ntr = (0.015 * 110 + 20*1.3 + 1.7*20)1000*9.8 = (1.65+26+34)9800=0.063= 6 m.

If there are fewer fittings and other elements, then less pressure will be required. For example, Ntr = (0.015*110+5*1.3+5*1.7)9800=(1.65+6.5+8.5)/9800=0.017=1.7 m.

Conclusion: This heating system requires a circulation pump with a capacity of 2.8 m3/hour and a head of 6 m (depending on the number of fittings).

How to determine the flow and pressure of a centrifugal pump

The performance/flow and pressure of a centrifugal pump depend on the number of revolutions of the impeller.

For example, the theoretical head of a centrifugal pump will be equal to the difference in pressure at the inlet to the impeller and at the outlet of it. The liquid entering the impeller of a centrifugal pump moves in a radial direction. This means that the angle between the absolute speed at the wheel entry and the peripheral speed is 90°.

Nt- theoretical head of the centrifugal pump.

u- peripheral speed.

c- speed of fluid movement.

α - the angle discussed above, the angle between the speed at the entrance to the wheel and the peripheral speed, is 90 °.

β =180°-α.

those. the pump pressure value is proportional to the square of the number of revolutions in the impeller, because

u=π*D*n.

The actual pressure of a centrifugal pump will be less than the theoretical one, since part of the fluid energy will be spent on overcoming the resistance of the hydraulic system inside the pump.

Therefore, the pump pressure is determined using the following formula:

ɳg- hydraulic efficiency of the pump (ɳg=0.8-0.95).

ε - coefficient that takes into account the number of blades in the pump (ε = 0.6-0.8).

Calculation of the pressure of a centrifugal pump required to ensure water supply in the house is calculated using the same formulas as given above. For a submersible centrifugal pump, use the formulas for a submersible well pump, and for a surface centrifugal pump, use the formulas for a surface pump.

Determining the required pressure and performance of a pump for a summer house or country house is not difficult if you approach the issue with patience and the right attitude. A properly selected pump will ensure the longevity of the well, stable operation of the water supply system and the absence of water hammer, which is the main problem in choosing a pump “with a large margin by eye.” The result is constant water hammer, deafening noise in pipes and premature wear of fittings. So don’t be lazy, calculate everything in advance.

The mere presence of a well does not mean that a country house or cottage will be sufficiently provided with water. Even in the best scenario, when the water pressure is enough to lift the pole to the surface, the autonomous system in the house will not function. In order for water to flow from all taps and household appliances to work, the minimum reserve must be 2.5 atmospheres, which a well pump can handle quite well.

Before you go shopping, you need to make the correct calculation of the operation of the well pump. It is short-sighted to buy a pump that cannot cope with the load, as well as to choose a “sophisticated” model whose power is enough for 3 wells like yours. In both cases, the purchase will be unjustified, and in both cases you will waste your money. We will look at how to carry out the calculation and how to use it as productively as possible in the conditions of a summer house or cottage.

Preliminary parameters

Before you decide to purchase a submersible pump, you need to take measurements of the well itself and understand which unit will be the best option. So we measure:

• hole depth;
• dynamic liquid level to determine the flow rate of the opening;
• statistical water level - the distance from the surface to the liquid surface;
• borehole pipe diameter.

To obtain water for domestic purposes, the best option would be a submersible pump - centrifugal or vibration, depending on the operating principle provided in the device. For deep wells without casing, it is not recommended to use a vibration device, since constant vibration will lead to shedding of sand and soil, gradual filling of the well and clogging of the pump.

Required water pressure

Let's start by calculating the required flow, which is the sum of all consumers available on the site. In addition, you need to analyze how much a person uses the liquid and calculate the maximum water consumption.

We need to find out what pressure there will be when working with a deep-well pump. To determine this indicator, it is better to carry out a couple of simple calculations, which will include the dynamic depth of the opening at a certain device performance, as well as the pressure loss and the height where the consumers are installed. These parameters are individual in nature, and therefore we can only talk about optimal indicators: in order to maintain normal pressure at 2.5 bar, the device must provide a liquid supply height of 70 m.

Consumption rate

So, first you need to choose the type of equipment, which can be submersible or self-priming. And to correctly determine what is right for you, you should carefully study all the characteristics and parameters. If there is a ready-made object on which you want to install equipment, then there must be a project.

Let's return to household needs. It is generally accepted that the average water requirement per person is 200 ml. If these 200 ml are consumed in a couple of hours, then a family with 4 people can consume about 0.5 m 3 / h. If water is used for additional needs, then consumption will increase to 1.5 m 3 / h.

Formula for calculating a pump for a well

Let's look at the simplest example. We have a family of 4 people. Let's say they live in their own house outside the city, and for their site we will take equipment whose load is 1.7 m3/h. We need to find out whether there will be enough pressure to supply water to the second floor of the house in the bathroom. To carry out calculations you need to know:

• standard value, let's denote it P and assume that it is 2.5-3 atm;
• the difference between the strongest point of water withdrawal and the dynamic level, which we will call ∆H;
• a value that shows the size of hydraulic losses - ∑∆P

We derive the general formula by which the pressure is calculated: H = ∆H + 10.2xP + ∑∆P and obtain the size of the minimum pressure N.

After all measurements have been taken, it is necessary to select equipment. It is worth choosing a unit that, in terms of its characteristics, will be closest to those that the calculation formula showed us. In addition, be sure to compare the parameters of the well itself and the pump.

If you are using a submersible pump, its diameter should be smaller than the hole.

Electrical characteristics

Electrical output is an important consideration when designing power cables as well as special electrical protection devices. There is one small nuance that distinguishes this characteristic from all others. To determine the electricity load, it is not necessary to carry out any additional calculations. It is enough to study the technical characteristics of the equipment, which are usually indicated in the passport. Also, in order for the work to be carried out normally and with a high level of safety, it is necessary to match the cable and the electrical power that the unit consumes.

When calculating the power of a well pump for water supply to an area, you need to take into account a number of nuances, and therefore, if you are not confident in the correctness of the calculations, it is better to contact specialists.

What criteria should you follow when choosing a pump?

For those who are not satisfied with the performance of old equipment, a couple of tips on how to choose a well pump that will be more productive will be useful. Let’s say that by choosing a centrifugal pump, you can avoid the fact that the well will be filled with sand. In order to obtain high quality water, it is better to install the device no less than 1 meter from the filter. When water consumption, it is necessary to take into account not only average figures, but also peak values. In addition, you need to ensure that there is enough water for technical needs. Good pressure will be provided by a pump with a power reserve of approximately 20%.

A decrease in pressure can be caused by the appearance of silt in the well or the use of filters. Independent calculations of a pump for a well based on pressure power may not be accurate, and therefore it is better to use the help of professionals in this matter.

Also important: the diameter of the device must be at least 1 cm smaller than the well in which it is used. This will make installation easier and will also increase the operating time of the pump.

In addition, in addition to the main characteristics, when choosing a device, you should pay attention to its immersion depth and the pressure that the device creates. The equipment may vary in diameter. There are those in which the indicators are small - 100 mm. Their appearance may resemble a kind of elongated cylinder, which can be lowered to the bottom of our well hole without any problems. There are also devices for wells, the diameter of which is larger, but the immersion depth is less. But they can be noted for the efficient use of engine operation.

Before installing the device, you must take a hose or pipe of the required length and size in order to connect it to the inlet of the pumping equipment. It is selected depending on the immersion depth. The presence of a check valve is also important, so if it is not included in the standard package, it is better to install it yourself. If this part is missing, the liquid will return back into the well.

It is better to entrust the installation of a device for pumping water to professionals, since the installation work is quite complex. In addition, you need to know that the equipment itself will not be able to perform a direct function. For this you need additional auxiliary devices, such as:

• Membrane tank;
• Electronic control unit;
• A sensor that shows pressure;
• Pressure gauge;
• coupling;
• Clamps.

Once you have all the parts, you can begin installing the unit. Before starting it, you need to check the pressure in the tank and that all connections are correct. When all installation work is done, the device can begin to function and supply water from the well. This unit makes it possible to provide water supply to any summer cottage, which is why it is in demand on the market. In addition, its capacity allows it to be used on an industrial scale.

Pumps are used to supply water from a well or well or to recirculate it. In order for the system to work efficiently and uninterruptedly, and also in order not to overpay for a model with excessive characteristics, they need to be selected. Let's consider how to calculate a pump for water supply and select the parameters of these units.

Water pipes

In addition to the calculation method in the usual way, we will also give several examples of working with online calculators.

First, let's look at cold water supply systems, that is, regular plumbing, then we'll touch on hot water supply (abbreviated as DHW). Moreover, we will not talk about the choice of powerful pumps that are installed at water supply network stations - our article is about the water supply of small houses and cottages.

If the house is connected to a central water supply, then in most cases the necessary pressure is created at water supply stations or water towers. Therefore, pumps in this case are usually not needed. The exception is in high-rise buildings, where normal pressure from the water supply does not allow water to be supplied to the uppermost floors - they are installed there.

Interesting fact. Columns of water 10 meters high create a pressure of one atmosphere (0.1 MPa), so the difference in pressure on the first and third floors is approximately this amount. If we take for example the tallest building in the world, the Burj Khalifa, with a height of 828 meters, then in order for the water to even reach the top floor, a pressure of about 84 tons of atmospheres is needed. Naturally, no pipes can withstand it, so the pumps are installed in stages across several floors.

With an autonomous water supply system, you cannot do without pumps. As a rule, they use either conventional (surface) or. With very rare exceptions, their drive is electric.

The choice depends on the specific situation or the wishes of the customer. Let's look at how they differ and the most important characteristics that we will need when carrying out the calculation.

Conventional pumps

They are almost exclusively used for water supply. In them, the liquid is captured by the blades in the center of the rotating impeller and is thrown due to centrifugal force to its perimeter, where the pressure pipe is located. In the center where water is taken, a vacuum is naturally created.

Attention. When starting such a motor without water (dry running), without encountering fluid resistance, the wheel, especially on powerful large pumps, can spin very quickly and break off the shaft or be damaged in other ways. Therefore, this situation is prevented by proper startup, installation of check valves at the inlet (they prevent water from draining from the housing) and the use of special automation.

Typically, two types of pumps are used - with an oil seal on the drive shaft and more modern ones with a floating rotor.

• In the first, the impeller drive shaft passes through the housing (scroll) in which the impeller rotates. This place is sealed with oil seals or mechanical seals. The shaft can rest on its own bearings, which are located in the console and connected to the electric motor through a coupling.
• Another option for such a pump is a monoblock. In it, the impeller is mounted directly on the impeller. The first type is more reliable and easier to maintain and repair. The second one is more compact.
• Pumps with a floating rotor do not have seals at the shaft passage. In it, as the name implies, the rotor of the electric motor is located in a housing volumetrically connected to the volute. The stator electromagnets create torque through the wall, the water cools the rotor and lubricates its bearings.

Such pumps are compact and reliable. The downside is the difficulty of repair - you can’t simply replace the motor; you need to completely disassemble the pump.

In addition, standard electric motors cannot be used in such a unit. However, they rarely fail and do not require maintenance throughout their entire service life (many manufacturers guarantee this).

Pump characteristics

Now let's move on to the most important thing.

The type of conventional pump selected for your off-grid water supply system affects the following:

• cost of installation of an autonomous water supply system;
• costs of its operation;
• frequency of maintenance;
• complexity and cost of installation;
• dimensions of the pump installation site.

Otherwise, when calculating, you need to focus on more important characteristics:

1. Suction depth: It determines the level below the pump from which it can draw water. It is usually determined in meters.
2. Pressure: It is expressed in pump outlet pressure.
3. Performance: how many cubic meters the pump can pump in an hour.

You also need to pay attention to such figures as energy consumption (power); with equal characteristics, it is advisable to give preference to more economical models. However, the price for them is usually higher, so it is advisable to calculate how long it will take for a more expensive model to pay for itself (however, this is an economic calculation).

If the service life is less than the payback period of an expensive pump, then, most likely, you should not overpay, but buy a pump that is more power-hungry.

They differ from ordinary ones in that they are immersed in water, that is, in the casing of a well, a well, or even an ordinary body of water. By design, they differ from conventional pumps in such features.

1. Most often, they have not one impeller, but several, up to a dozen, located one behind the other. The suction of one is connected to the output of the next (labyrinth system).
2. If conventional pumps most often have a horizontal shaft arrangement, then deep-well ones are always vertical. This is due to their location in well casing pipes of limited diameter, which are also vertical (installation in a well or reservoir is a special case to which designers pay little attention).
3. Electric motors are also of a special design. They do not have casing fins, as they are cooled by water.

Attention. You cannot run a deep-well pump not submerged; it is not designed for such a mode and can immediately burn out.

Also, the motors of these units have more elongated dimensions along the axis with a smaller diameter. This is also related to installation in wells.

In addition to centrifugal pumps, vibration and submersible pumps are also used for small water supply systems. This, for example, is the well-known “” (pictured below). According to the principle of operation, it is similar to ancient piston pumps (including bicycle ones), although the piston stroke is shorter, the oscillation frequency is higher (that’s why it is called vibrational), and an electromagnet is used for the drive.

Despite the slightly worse characteristics compared to centrifugal deep-well pumps, everything that is said in our article about them fully applies to the “Rucheyok” and its analogues.

Characteristics of deep-well pumps

The definitions of the characteristics of deep-well pumps are exactly the same as for conventional ones. The only difference is that the suction is not regulated for them, since the vacuum at the inlet is not important, the unit is already surrounded by water.

But many deep-well pumps have an order of magnitude greater pressure than conventional ones. When installed in a deep well, they must immediately overcome the pressure in a long riser pipe, and then create the required pressure in the water supply.

They are also considered to be somewhat more economical due to water cooling. But this advantage is minimal over pumps with a floating rotor. They also use a similar principle, although the stator does not have contact with the liquid on all sides. Completely washing the pump with water gives minimal savings of a fraction of a percent.

Which pump to choose: deep or surface (regular)

Quite a difficult question - let’s compare their advantages and disadvantages.

Conventional pumps

Pros:

• They are easier to mount on a surface.
• Inspection, maintenance and repair are also easier.
• Typically, conventional pumps are cheaper.

Minuses:

• A place or room for installation is required.
• Protection against dry running is required.
• In terms of suction depth, they are inferior to the pressure of deep-well pumps, so they cannot be used to draw water from deep wells.

Pros:

• Can work in deep wells.
• They do not require arrangement of installation sites. Water from the riser pipe can be directly supplied to the water supply system.
• If the pump is immersed below the minimum water level in a well, well or reservoir, it is protected from “dry running”.

Minuses:

• When installed in wells deeper than 10 meters, removing the pump along with the water-lifting pipe for inspection and repair with your own hands is often impossible; lifting mechanisms must be used.
• If for some reason the pump was torn off from the pipe and insurance (unless, of course, you forgot about the latter), it is quite difficult to get it out.

Interesting fact. The author of this article had to remove the accidentally missed pump using a special trap. After it was “saved,” five more units, mostly almost completely destroyed by corrosion, were pulled out of the well, which were lost by previous operators over the more than thirty-year history of the engineering structure.

• The power cable supplying the unit must be protected from exposure to ambient water. Often its breakdown, which occurs from damage to the insulation, leads to the need to remove the pump, and this, as we said above, is difficult.

Therefore, we will give one piece of advice: if you do not have a very deep well, or even more so, it is just a well and there is space for installation on the surface, you should still give preference to conventional pumps. They are cheaper and easier to operate.

Often, as an advantage of conventional pumps over deep pumps, they also consider the fact that the deep pump is protected from contamination only by a mesh filter on the casing, while the regular one can be additionally protected by multi-stage filters on the suction.

This is a false fact:

1. Any water purification installation works stably only with sufficient pressure, that is, it must be installed after the pump.
2. Pumps for water supply (no matter deep or ordinary) are designed for the presence of impurities in the source water, and they do not significantly reduce their service life. Of course, if you do not pump a mixture of sand and water directly, the latter effectively retains the mesh filter.

Now, having dealt with the choice of pump by type, let’s move on directly to choosing it by characteristics.

A little about pressure units

Everyone knows the usual atmospheric pascals well from school, but less well-known units may also be present in the pump characteristics.

1. Meter- this is a meter of water column. As mentioned above, it is equal to one tenth of the atmosphere.
2. Bar- a non-systemic unit (but approved for use in our country) approximately equal to one atmosphere.

Attention. You may also come across such an incomprehensible term as “excessive pressure”. Don’t pay attention, almost all instruments and calculations for water supply use the term “pressure” to mean this.

The absolute pressure will be one atmosphere higher, that is, the pressure that already exists on the surface of the earth, where water supply systems operate. Even in a glass, water is under an absolute pressure of one atmosphere.

Selection (calculation) of a pump for water supply according to characteristics

Let’s make a reservation right away: we do not calculate water supply pumps using hydraulics, that is, we do not take into account the resistance to water flow in pipes and on shut-off elements. For small water supply systems of a private home, it is scanty, and the calculations are complex.

Note. Some pumps have parts that are made of materials that, according to sanitary and hygienic standards, are unacceptable for use in water supply networks. Therefore, you need to choose models that are approved for these purposes.

To select a pump we need to take several steps, the instructions will be as follows.

Choosing performance

The first thing you need to focus on is water consumption per person per day, it is 400-500 liters. If you have a storage tank of sufficient capacity (like a water tower), you can follow these steps.

1. We multiply the average consumption by the number of people living in the house (for example, an average family of four), plus one person for possible guests (if you have them): 500x5 = 2500 liters.
2. Divide by the number of hours per day: 2500:24 = 104 l/h, this is the average hourly consumption.
3. Since it is desirable that the pump does not work constantly in order to avoid overheating and failure, we additionally divide it by the time of its operation. It is usually recommended that the operating time should not exceed 80%, that is, we divide by 80:100 = 0.8, we calculate: 104:08 = 130 l/h. We take this characteristic for the pump as well.

But, as a rule, storage tanks are not used in water supply systems of small houses. The most common scheme is a combination of a pump and a small-sized tank (hydraulic accumulator), as well as automation systems. Usually they buy an already assembled block of these devices from sellers, and in everyday life (which is not entirely true) they call them pumping stations.

So, for example, if mom decides to wash the dishes, dad decides to wash his hands after repairing the car, one child takes a shower, and the other uses the toilet, and the washing machine is working, then the water consumption may be much more than the daily average. Therefore, the calculation of the water supply pumping station and similar systems should be carried out based on these peak analyzes.

To do this, we count all the available water fixtures in the house. Then we take their hourly expenses. To do this, you can use the table in Appendix 2 to SNiP 2.04.01-85. It is shown below.

Next, we make a list of all plumbing fixtures and their hourly costs. Moreover, we take not only cold water, but the total flow rate, because hot water is heated cold water, which is taken from the same water supply system.

Device name	Hourly water consumption, l/h	Number of appliances in the house	Their total consumption
Sinks with mixer tap	60	5	300
Washing	50	1	50
Bath	300	1	300
Foot bath with mixer	220	1	220
Shower with deep tray and mixer tap	115	2	230
Hygienic shower (bidet)	75	1	75
Toilet with cistern	83	2	166
Urinal	36	2	72
Watering tap	1080	1	1080
Total			2493

As a result, we obtained the maximum water flow rate in the water supply of your home - 2493 liters per hour. This figure is even a little overestimated, since it is unlikely that all devices will be turned on at the same time; it can be reduced by a factor of 0.9-0.8. We get: 2493x0.8=1994 l/h. True, if the house is small and there is only one kitchen and bathroom, this is not worth doing.

Based on our resulting peak water flow per hour, we will select the pump performance in the future.

Selecting the pressure

Here the choice depends on whether it is a deep-well pump or a regular one.

• For a conventional pump, everything is as simple as possible: according to standards, the pressure in the water supply should be in the range of 0.05-0.5 MPa, that is, from half to five atmospheres. As practice shows, for normal operation of washing machines, dishwashers and other household appliances, it is desirable that the pressure is not less than 1 atmosphere, i.e. 0.1 MPa, so we will choose a pump with exactly this pressure.

If you have a cottage with more than three floors (which is rare), then you need to make sure that there is normal pressure at the top. With a standard ceiling height of about 3 meters, there will be no pressure on the fourth floor, so we add 0.1 MPa.

That is, in most cases, when selecting a pump for water supply, a pressure of 1-1.5 atmospheres (0.1-0.15 MPa) is sufficient.

• When choosing an option with a unit installed in a well, calculating the water supply pump for pressure becomes more complicated, but not much - you just need to take into account its immersion mark. That is, if water is taken from a depth of 15 meters, to the pressure calculated, as in the previous case, we add 1.5 atmospheres (15:10 = 1.5) or 0.15 MPa (15:100 = 0.15 ). We consider: 0.15 + 0.1 = 0.25 MPa, and we will be guided by this figure when choosing a specific pump model.

Suction depth (suction)

The easiest parameter to select. For deep-well pumps it is not needed and is not described in the characteristics at all, since water is taken from the level at which the pump is located.

In the case of a conventional surface pump, it is necessary that this characteristic be slightly greater than the difference between the elevations of the intake and the location of the pump. The reserve is needed for unforeseen situations, for example, during a drought the level will drop and the intake will have to be lowered.

It is easy to select, for example, the pump is located at ground level, and water is drawn from a depth of 10 meters. This means that the suction must be more than 10 meters.

It is not worth giving a multiple supply; if the intake is located at a depth of 1 meter, then you should not take a pump with a suction depth of 15, 3-5 is enough. This is due to the fact that the greater this characteristic, the more complex and expensive the pump.

Direct selection

When all the parameters are known, you can select a pump or station from price lists and directories. You don’t even have to select a model yourself. Almost all sellers' websites have filters into which we enter the necessary characteristics, then a list of the most suitable models is displayed on the screen.

For example, to select on the Grandfos website, you just need to take a few steps. We need a surface pump with a capacity of 1.5 liters per minute with a lift height (suction) of 5 meters and a pressure of 1.5 atmospheres (15 meters). Let's do the following.

• On the tab at the top, click on the “surface pump” tab.

• Then you can enter the necessary parameters in the filter on the right of the page. Additionally, you can select the price range, brand, power, drive type (electric motor, internal combustion engine), etc. If the calculation of the water supply station was carried out, then you can find it.

• After this, we press enter, and our page displays units that meet the specified characteristics.

• Additionally, you can select the order in which the pumps will be displayed on the page. That is, options are possible for increasing or decreasing price, popularity, or immediately newer or older models and vice versa. To do this, click on the buttons at the top of the page.

Selecting a pump for domestic hot water

The selection and calculation of pumps for hot water supply is not much different from the selection of units for cold water supply. But you need to take into account some features.

1. When calculating the amount of water per person, we take the norm to be 140-150 liters per day.
2. To calculate peak flow rates for plumbing fixtures, you can use the same table from SNiP 2.04.01-85, which is given above - in addition to the cold water flow rate, it also shows the hot water flow rate, which is naturally less.
3. When choosing a pump pressure, you need to focus on the pressure in the cold water supply. These numbers must be equal, otherwise, with faulty mixers, hot water can be squeezed into cold water and vice versa; the network in which the pressure is higher will displace liquid from the pipelines where it is lower.
4. The depth of lift (suction) is not important to us. Water is supplied to the pump inlet under pressure.
5. Not all pumps can operate at elevated temperatures. You need to choose only models designed for hot water supply networks.

Selecting a pump using an online calculator

If you want to make it easier to calculate a water supply pump, you can use online calculators. Some of them make the calculations even overly accurate, while some, on the contrary, contain many errors. Some give only parameters according to which you need to independently select a model from catalogs, and some immediately give out the pump model.

Let's look at a few examples of working with these calculators.

It should also be noted that most often the result is a specific pump that the site owners produce or sell. Therefore, when using a calculator, you may not choose the most efficient or reliable model. The choice is yours.

Calculator on the WPCALC website

We work with it as follows:

• We immediately go to the page with a short introduction that describes deep-well pumps and their purpose.

• Then scroll down a little and go directly to the calculator.

• We enter the parameters: well depth, distance to water, area of ​​the site and the number of people living in the house.

• Next, enter the number of plumbing fixtures in the house.

• Click on the green “Calculate” button.

• And using it we read the calculation parameters. It's just performance and drive. You need to choose the pump yourself.

It should be noted that this is not the most reliable calculator. It does not take into account what pressure we want to set in our DHW system, and also (verified) does not take into account peak discharges.

Calculator on the website of the company "Gidrotekhnika"

Another simple calculator at: http://gidrotehnica.ru/calk1/. Unfortunately, it does not give out parameters, but selects specific pumps. But it also calculates the power of the pump for water supply, and it is easy to work with.

• Open the page with the calculator.

• Then enter the distance to the water surface in the well, for example 15 meters.

• Select the minimum diameter of the casing pipes by checking the corresponding button. We chose over 120mm.

• Then we select the type of system, more precisely the control, manual or automatic, also checking the box. We chose the first one.

• Then, under the “Quick selection” item, we determine the water consumption from three options depending on the number of people living in the house. We chose more than three people. Of course, the accuracy of the calculation is low, since between three people and a large family the difference in water consumption is significant.

• Next, you can check the box next to “Detailed selection” and indicate in the window below the maximum height of the plumbing fixture in the house. This is necessary for a more accurate calculation of pressure. For example, enter 4 meters.

• Next, click the “Search for Equipment” button or just the “Enter” key on the computer.

A page is displayed on the screen in which the table shows the recommended types of pumps and their parameters. By clicking on the name of the pump, you can go to its page in the catalog of the online store of the company "Gidrotekhnika"

Calculator on the Aquatek website

This is a pretty good and accurate calculator, but, unfortunately, it is designed only for specific models of a given manufacturer and also calculates only deep-well pumps. Link to the calculator: http://www.aq-pump.ru/calculator/.

It immediately selects specific pumps of a given brand, but if desired, the results can also be used to select a deep-well pump from other manufacturers.

It should also be noted that the input and calculations are a little complicated, but we will help you figure it out.

• We immediately go to the calculator page, as always there is an introduction at the top.

• We scroll through it and get to the data entry fields, they are located on the left. We immediately enter the type of building: residential building, hotel with bathtubs or showers in each room. There is no need to enter it manually, just click on the field and select it in the opened filter.

• The next step is to enter the maximum number of people living in the house. The window for this is below. Numbers can be entered either from the keyboard or using the arrows located on the right side of the input window. The up arrow increases the value, the down arrow decreases.

• Next, we need to enter the number of plumbing fixtures and household appliances in the same way as the number of residents. Even washing machines and dishwashers are taken into account.

• We immediately introduce the dynamic water level in the well. That is, the depth of the water mark when using a well (as opposed to a static one, which is set when there is no extraction).

By the way, if it is not clear what a dynamic level is, you can touch the question mark located at the top right above the input window with your cursor and an explanation will open.

• Next, enter the number of floors in the house, the distance from the house to the well and the height of the floor. Everything is clear here.

• Next is a not very clear point: “The number of cylinders in the water treatment system.” These are bulk-type installations for water purification; conventional in-line mesh filters are not taken into account. At this point you can also click on the question mark for clarification.

• This completes the data entry. The “Calculate” button common to many calculators is missing. To find out the result, look at the graph at the top right of the data entry columns.

Of course, it is not immediately clear where the result is. Notice the red dot on the graph. It constantly moves as data is entered, indicating that calculations are being carried out simultaneously for the values ​​already entered, the rest are taken by default.

By its position we see the calculated pressure and productivity. The vertical axis shows the pressure, in this case about 50 meters, and the horizontal axis shows the productivity, in this case about 2 cubic meters per hour.

You can find out the numbers more accurately by hovering the cursor over the point, then a hint with the exact results will pop up.

We received a head of 48.87 meters and a productivity of 2.101 cubic meters per hour. Using them, you can select a pump from third-party catalogs.

If we choose Aquatek brand products, then we look at the lines that are plotted on the graph. These are the characteristics of the pumps. In our case, the point is almost on the yellow line. See below for color codes.

As we can see, our calculations correspond to the Aquatek SP 3″ 3-60 pump. You can click on the name of the pump and go directly to its page, where you can find out more detailed information about it and place an order.

Pump page "Aquatek" SP 3″ 3-60

That's all we wanted to tell you about calculating the performance of a water supply pump and its other characteristics. Additionally, you can watch the video in this article, it also describes the methods for selecting characteristics.

We hope the article was useful to you and helped you understand the principles of its implementation. It’s great if you were able to practically select the unit you need and install it in your home. Clean water and comfort in the home.