How to choose a pumping station for home and summer cottages

Recommendation points

• What well parameters are required for the calculation
• Pump selection by performance
• Compliance with well parameters
• Technical aspects
• Submersible and surface pumps

Often, your own well or well is the only source of water for a house or summer cottage. Of course, water must be extracted from the depth in some way, for which several series of special hydraulic equipment have been developed. Today we will talk about the types of pumping equipment and how to choose a pump for your home and summer cottage.

What well parameters are required for the calculation

For each well, pumping equipment is selected individually. This approach is facilitated by both the special operating conditions and the very different configuration of the plumbing system. The desired technical performance of the pump is determined by many factors, but first things first.

The height of the water rise is of primary importance and it directly correlates with the pump power. Of course, the design parameters of the well are far from real: the mirror can rise and fall up to a dynamic level. The maximum one-time water intake also tends to change over time, because the time for complete pumping out can increase due to the seasonally increased flow rate..

When calculating the well equipment, it is the minimum estimated production rate that is interesting. Ideally, the well should never be completely emptied, which means that the average daily water intake should be equal to or exceed consumption – this is the most favorable option. Therefore, the pump capacity (flow rate in m³/ h) should not be overestimated too much.

Pump selection by performance

This is the most problematic stage in the selection of pumping equipment. While the parameters of the well and the system are easy enough to correlate with the concepts of lift height, line length and desired operating pressure, then it is not so easy to determine consumption at different time periods..

The reference point in this is the volume of the well lowering – the amount of water that can be taken from it at a time at zero flow rate. If the pump capacity is higher than the flow rate (and this is almost always the case), then the uptime is calculated as the ratio of the volume of reduction to the difference between the inflow and the capacity of the station.

The mode of operation of the water supply network and the rate of well recovery are also important. As a general rule, it can be assumed that at least 4–5 hours a day, water is not pumped out of the well, which means that the static level is fully restored. Therefore, the daily calculation will be enough.

The most pronounced periods of active water consumption are the use of toilets and watering of crops on the site. For these periods of increased consumption, the general mode of use is compiled, and the pump performance is also selected. For example, a 150-liter bath should be filled three times a night for each family member. With a well debit of 200 liters and a reduction volume of 50 liters, it turns out that in order to supply other consumers during this period, the pump capacity should be in the range of 250-300 liters per hour.

Along with the main consumers, minor ones can also be taken into account: cisterns, washing machines and others like them. The pump capacity during the addition of corrections can be increased up to 700–1000 l / h, if a simultaneous intake from all points is required. It is no longer possible to overestimate the performance bar: falling below the dynamic level is fraught with breakdowns due to dry running.

Compliance with well parameters

An interesting detail lies in the determination of the suction depth – one of the most important parameters of the pumping unit. Contrary to popular belief, this is not the absolute depth of immersion of the pump or suction filter into the well, measured from the surface, but the depth of the mirror at a dynamic level. There is no fundamental difference to the pump at what depth to work, because the main work is done only to raise the water above the mirror level.

Another physical trick is that the suction depth can vary in proportion to atmospheric pressure and altitude. The thinner the atmosphere, the less it promotes extrusion. Due to this factor:

1. Achieved natural protection of the submersible pump from air entering the water supply.
2. The expediency of placing an external pump at the lowest point of the system is explained.

The suction depth of surface pumps is usually quite shallow: the maximum is 40–45 meters for advanced specimens with an external ejector operating in limestone wells. At the same time, pumps of a more traditional design can suck from a depth of 15 meters. It turns out that for wells of 20-30 meters there is simply no optimal class of equipment.

Data for calculating the pump for the well: 1 – check valve with filter; 2 – well; 3 – suction pipe; 4 – pumping station; 5 – ground level; 6 – basement; 7 – consumers of water in the house

This can impose additional restrictions, for example if the maximum suction depth is above the dynamic level. If it is simply impractical to buy a more expensive station, you have to sacrifice the dynamic level and, as a result, the one-time reduction volume. This means that the debit adjustment must be recalculated..

The height of the pump head is the difference between the level of its installation and the highest point of the draw-off. Please note that the hydrodynamic resistance of the pipes of the system can no longer be neglected here. In contrast to the relatively straight section between the suction filter and the pump, the outgoing line is characterized by a narrowing capacity, numerous bends, fittings and valves. On average, power losses due to frictional forces in pipes can reduce the declared lift height by 10-30 meters.

Technical aspects

The choice of a pumping station looks completely different from the point of view of technical excellence and overall reliability. To confidently navigate, you need to understand well some details of the internal structure..

Let’s start with the most common surface pumps with a suction depth of 7-10 meters. Inside, they have a conventional impeller, that is, the pumps work due to the centrifugal force of scattering water. They are popular in pressure boosting systems, but such a technique should not be installed in a well (with the exception of Abyssinian).

A pump with an ejector unit is not critical to the presence of air in the system at a concentration of up to 50%. This facilitates the device for automatic drainage of water from the main in winter, allows you to increase the suction depth to 15–20 meters. The remote ejector, as mentioned, doubles this figure, but at the same time the complexity of the pump and its piping increases by an order of magnitude, and therefore, the potential number of breakdowns of low-quality equipment increases.

Pump station with a remote ejector: 1 – filter with a check valve; 2 – ejector; 3 – suction pipe; 4 – supply pipe; 5 – pumping station

The weakest points of most pumps are the body parts, the plastic impeller, the engine manifold, and the automation. Hydraulic accumulators sin with drying out of the rubber membrane and corrosion of the connecting pipes. When choosing, the study of mock-ups that demonstrate the internal structure of the equipment is encouraged..

Submersible and surface pumps

As you may have figured out, sometimes it makes sense not to consider a traditional pumping station as the only water supply option. Often, it is the hybrid versions of the systems that allow solving specific problems.

The first thing that is needed for this is the availability of a submersible pump for placement in the well. Wells deeper than 40 m are initially designed only for this method of water production, but in less deep ones, 130 mm may not be necessary to install a pump of the smallest standard size. Also, we must not forget that the pump reduces the available volume of water in the well, sometimes reducing the uptime by more than an hour..

Pressure switch for pumping station

As for the automatic station, connecting a hydraulic accumulator with a pressure switch is also possible in this case. True, the system will be constantly filled with water, which means that it must be thoroughly insulated. More useful would be a combination of an electronic pressure regulator with an air release valve installed directly at the head of the well. Of the additional costs for installing a hybrid station, only the power cable is allocated, which must correspond in cross section with such a significant length of the power line.