Grundfos 77S SP Submersible Well Pump

A nominal 77 GPM pump family for irrigation, commercial and industrial water supply, groundwater transfer and waterworks. Ten hydraulic sizes cover low-lift through higher-head duties, with 4-inch and 6-inch motor choices on selected larger models.

Grundfos 77S belongs to the SP range of multistage stainless steel submersible pumps. The complete pump combines the hydraulic pump end with the Grundfos submersible motor identified by the selected part number. Stainless steel impellers, chambers, strainer, straps and cable guard provide a corrosion-resistant construction for clean-water service. Stage count determines the available head within the family.

Water-lubricated bearings incorporate channels that allow sand particles to pass with the pumped water. An inlet strainer limits entry of larger particles, a built-in check valve limits reverse flow after shutdown, and a stop ring limits axial shaft movement during startup. The pump must remain submerged and operate within the permitted sand content and motor-cooling conditions.

Assemblies with 4-inch motors fit 4-inch and larger wells; 6-inch motor selections require a 6-inch minimum well. Select the complete-pump part number using horsepower, voltage, phase and motor/wiring configuration. Control equipment and installation accessories are ordered separately.

The 77S family is rated at 77 GPM. The table below gives the manufacturer's nominal total dynamic head for each hydraulic model at rated flow. A head range reflects differences among the listed motor and electrical configurations. These figures are nominal duty data, not shut-off head or maximum well depth.

To select a pump, add the lift from the pumping water level to the delivery point, the required outlet pressure expressed as head, and piping friction loss. Confirm that the selected pump curve meets that total head at your required flow. Use the pumping water level under load, not the drilled depth of the well.

• Stainless steel hydraulics. Standard S-series impellers and chambers are AISI 304 stainless steel, supported by stainless external components.
• Multistage selection. Choose the stage count and motor rating that deliver the required flow and total dynamic head.
• Sand-handling bearing design. Water-lubricated bearings and sand channels reduce abrasive wear in suitable well-water service.
• Built-in check valve. Helps prevent backflow after shutdown and reduces the risk of water hammer.
• Upthrust control. A stop ring limits axial movement of the shaft during startup.
• Protected inlet and cable routing. The inlet strainer limits larger-particle entry, while the screw-mounted cable guard secures the motor lead along the pump.
• Matched submersible motor. Each complete-pump SKU includes the motor specified for that electrical and mechanical configuration.
• Serviceable construction. The 35S-77S family uses a smooth-shaft construction with separately identifiable hydraulic and motor components.

• Agricultural and horticultural irrigation
• Commercial water supply and waterworks
• Industrial clean-water supply
• Groundwater transfer and tank filling
• Groundwater lowering and dewatering within the specified water-quality limits

Type key. In 77S07-2, 77 identifies nominal flow in GPM, S identifies the standard stainless steel series, the following number identifies motor horsepower, and -2 identifies the number of impellers. The number after the hyphen is a stage count, not a head rating in feet.

Choose the variant. Select HP - Voltage, then Model, then Motor & Wiring. Use the complete-pump part number to place the order. The same hydraulic model may have multiple motor configurations and part numbers.

What is included. Hydraulic pump end and the motor specified by the selected complete-pump SKU. Control boxes, starters, external VFDs, pressure switches, tanks, drop cable, drop pipe and other installation accessories are ordered separately.

Controls. Match the control box or starter to the selected motor horsepower, voltage and phase. Where dry-running or additional motor monitoring is required, specify suitable separate protection equipment.

The free Grundfos GO app gives you setup, status overviews, technical product information and live operating parameters from an iOS or Android device. Pair the pump directly with your phone, no extra module needed.