Pedrollo 4SR 4-Inch Submersible Borehole Pump

4-inch sand-resistant submersible borehole pumps for water wells up to 576 m head

The Pedrollo 4SR is a series of 4 inch multistage submersible pumps for clean water in boreholes and wells. The 50 Hz datasheet covers the 4SR-S range, with floating impellers, and the 4SR-N range for higher flows, with flow up to 450 l/min (27 m3/h) and head up to 576 m. Pedrollo recommends the pumps for clean water in domestic, civil and industrial applications: water distribution coupled with autoclave tanks, irrigation, washing systems and pressure boosting.

Pedrollo states that the floating-impeller 4SR-S design is exceptionally resistant to sand wear, with a durability it claims is ten times higher than other global market pumps, and that a patented inductor improves priming in wells with air/water mixtures or gas-bearing water. Treat the durability comparison as a manufacturer claim; the figure to design with is the stated sand limit of 200 g/m3 for the 4SR-S and 150 g/m3 for the 4SR-N.

Technical specifications

Model codes and example duty points

A 4SR code reads frame, then number of stages, then hydraulic type and motor: 4SR 4/22-S-PD is the 4SR 4 frame with 22 stages, floating impellers (S) and a 4PD oil-filled motor; a single-phase pump adds the m (4SRm). Frames in the datasheet are 1, 1.5, 2, 4, 6 and 8 in the S range and 10, 12, 15 and 18 in the N range. Examples from the first point of the published tables (the head falls as flow rises):

Selection and installation notes

Select by required flow first, to choose the frame, then by head to choose the number of stages. Check that the water temperature stays at or below +40 C, that sand content is within the limit and that the well gives the minimum 8 cm/s cooling flow across the motor. In reservoirs, rivers or lakes, or in a wide casing, Pedrollo lists an external cooling jacket kit as an option. The pump should hang on the delivery pipe at a depth that keeps it fully submerged during operation, with a stainless steel safety cable fixed to the coupling on the delivery port, a check valve in the line and level probes or a control panel for dry-run protection.

To compare with a borehole pump from another manufacturer see the Grundfos SP submersible borehole pump, and browse the pumps category for other duties.

4SR-S or 4SR-N: which hydraulic to choose

The duty point – required flow at the total head, including static water level, drawdown, pipe friction and delivery pressure – decides the model code. Choose a pump whose best efficiency area covers the normal operating point rather than the extreme end of the curve.

Operating in Oman and GCC boreholes

• Groundwater in many areas is warm and can be brackish. Check that the water temperature stays within the +40 °C limit and confirm material suitability with the water analysis when salinity is high.
• Newly drilled wells often carry sand until they are fully developed. Develop the well properly before installing the final pump to stay within the stated sand limit.
• Long rural feeders and generator supplies cause voltage dips. Protect the motor with a suitable control panel, and consider a soft starter or drive for larger ratings.
• Respect the limit of 20 starts per hour; size pressure tanks so the pump does not cycle too often.
• If the pump is installed where the 8 cm/s cooling flow cannot be reached, for example in a wide well casing or above the screen, fit a flow sleeve.
• Protect against dry running with level electrodes or a dry-run relay, since falling water tables are common in summer.

What to include in your RFQ

• Required flow and total head, plus well diameter and depth, static and dynamic water levels.
• Supply voltage and phase, and motor preference (4PD or 4PS).
• Sand content and water analysis if available.
• Whether cable, control panel, check valves or riser pipe should be quoted.

Documents and quotation

The Pedrollo 4SR 50 Hz datasheet (10 pages, EN) lists the full performance tables, dimensions and weights by model, materials and installation diagrams is attached to this page and is the manufacturer’s own document, not a Seven Star summary. The installation manual from the Pedrollo product page covers cable, cooling and electrical connection.

Before ordering confirm the static and dynamic water level, casing diameter, sand content, motor type (4PD or 4PS), voltage and frequency, and cable length. Seven Star LLC, an independent supplier in Muscat, quotes the Pedrollo 4SR against your duty point and delivery requirement; send the document tag, flow, head and liquid so the right size can be confirmed before an offer is issued.