Grundfos SQFlex 6 SQF-3 Solar Submersible Pump


Last updated on June 19, 2024 12:03 am


Grundfos SQFlex 6 SQF-3 Solar Submersible Pump

The Grundfos SQFlex solar pumps can be directly powered by solar or wind power or can be run on an inverter, a generator, a battery or the utility grid, or any combination of these sources. Virtually any source of power, 30-300 VDC and 90-240 VAC, can be used to run the pump. They can operate on a series string of PV modules with a total peak power voltage over 30 volts, but the pumps efficiency will be much higher at voltages over 100 VDC. SQFlex 3 and 6 pumps will fit into a 3″ well.

Seven pump models can deliver from 2 gpm at 600 feet to 65 gpm at 20 feet of head with a 1 kilowatt solar array or less. Helical rotor pumps (models 3, 6 and 11) for high head applications and centrifugal pumps for low head applications assure a pump that is efficient for any use. The SQFlex has built-in protection from dry-running, overload and overheating.

SQFlex submersible pumps have a 2 year warranty from the date of purchase. A 5 year extended warranty is available separately.

The Whisper 200-150 V wind generator can be connected directly to an SQFlex pump. Please contact us for information.

Optional Controls

The CU200 interface box communicates with the pump and monitors operating conditions. Built-in diagnostics indicate faults and dry-running, display operating status, power consumption and water level switch input. The water level switch interfaces with the CU200 control to turn off the pump when a tank is full.

The IO100 is a simple control box with cable terminations and a manual on/off switch. It is a great interface between a solar array and the pump to allow you to turn off the high voltage array when working on the pump.

The IO101 is an interface for using AC backup on a solar pump. An automatic transfer switch disconnects the solar array when AC power from a generator, utility connection or inverter is present. When AC power stops, it automatically reconnects the array to let the sun continue pumping.

The IO102 interface unit is used for systems powered exclusively by a wind turbine or by a combination of wind and PV.

You can use several controls if you need more features than one control can provide.

The SQFlex pumps will not function with a GFCI in the supply circuit, and should not be used where a GFCI is required.

The 3 SQF, 6 SQF, and the 11SQF are helical rotor type pumps. All others are centrifugal. All SQF pumps are 17 to 23 pounds in actual weight.

Model Number Type Max Head Max Flow PV Watts (Min-Max) ** Pump Diameter (Pipe Size)
3 SQF-2 Helical Rotor 360 Feet 3 GPM 100-340 3″ (1″ NPT)
3 SQF-3 Helical Rotor 600 Feet 2 GPM 130-600 3″ (1″ NPT)
6 SQF-2 Helical Rotor 360 Feet 6 GPM 100-650 3″ (1″ NPT)
11 SQF-2 Helical Rotor 300 Feet 11 GPM 50-900 3″ (1-1/4″ NPT)
16 SQF-10 Centrifugal 210 Feet 20 GPM 400-1400 4″ (1-1/4″ NPT)
25 SQF-3 Centrifugal 45 Feet 40 GPM 120-760 4″ (1-1/2″ NPT)
25 SQF-6 Centrifugal 90 Feet 39 GPM 130-1400 4″ (1-1/2″ NPT)
40 SQF-3 Centrifugal 45 Feet 38 GPM 200-800 4″ (2″ NPT)
40 SQF-5 Centrifugal 90 Feet 70 GPM 300-1400 4″ (2″ NPT)
60 SQF-3 Centrifugal 45 Feet 85 GPM 20-1400 4″ (2″ NPT)






  • Max Power Input = 900W
  • Output = 1″ NPT
  • Net Weight = 18 lbs
  • Power supply to pump 30-300 VDC, PE.
  • Run-up time Depends on the energy source.
  • Start/stop No limitation to the number of starts/stops per hour.
  • Enclosure class IP 68.
  • Motor protection- Built into the pump.
  • Protection: dry running by means of a water level electrode
  • Protection: overvoltage and undervoltage
  • Protection: overload
  • Protection: overtemperature
  • Conductivity ≥ 70 μs/cm (micro siemens).
  • Radio noise The SQF complies with the EMC Directive 89/336/EEC.
  • Approved according to the standards EN 61000-6-2 and EN 61000-6-3.
  • Power factor PF = 1.
  • Operation via generator: Voltage: 230 VAC –10%/+6%.
  • The generator output must be • minimum 1000 W (helical rotor pumps) • minimum 1500 W (centrifugal pumps).
  • Borehole diameter 3 SQF, 6 SQF, 11 SQF: Minimum: 3 in.
  • 16 SQF, 25 SQF, 40 SQF, 60 SQF: Minimum: 4 in.
  • Installation depth Minimum: The pump must be completely submerged in the pumped liquid.
  • Maximum depth: 500 ft below the static water table (220 psi).
  • Suction strainer
  • Holes of the suction strainer:
  • 3 SQF, 6 SQF, 11 SQF: ø0.090 in.
  • 16 SQF, 25 SQF: ø0.10 in.
  • 40 SQF, 60 SQF: 0.16 in x 0.80 in.
  • Pumped liquids pH 5 to 9.
  • Sand content up to 50 ppm.
  • Marking CE.