Grundfos 25 Sqf-3 Sqflex Solar Pump


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SKU: GRU8351 Category:


The Grundfos SQFlex solar water 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)



SQFlex Pumps

SQFlex PumpsThe complete SQFlex pump range consists of 7 different pump sizes: 4 centrifugal and 3 helical rotor pumps. All pumps are fitted with the same size motor which, together with the new sizing tools, makes system sizing simple.

SQFlex – Features

SQFlex pumps have build-in protection features that protect the pump itself and in many cases the well. Among these features are:

  • Protection against dry-running, overloading and overheating
  • Automatic restart when water returns to the well or when the motor temperature returns to the safety range
  • Continuous load condition and voltage monitoring

SQFlex – Applications
With the advances in pump technology over recent years, areas that would previously have been considered uninhabitable or not supportive of life have become viable and attractive. With the new SQFlex system, Grundfos can consolidate these areas and pioneer further into new territories: Consolidating by upgrading older unreliable pump technology, and pioneering by providing more stable and low-maintenance pumping solutions in even more remote areas.

Potential SQ Flex applications include:

  • Live stock watering
  • Remote Homes
  • National/State Parks
  • Irrigation
  • Remote Camps
  • In locations where power is scarce and water is a necessity.
Model TDH Range (Ft.) Nominal GPM Length (In.) Output Size Pump Type
3 SQF-2 120 – 390 3 47 1” NPT Helical Rotor
6 SQF-2 120 – 390 6 48 1” NPT Helical Rotor
11 SQF-2 40 – 300 11 49 1 1/4” NPT Helical Rotor
25 SQF-3 0 – 40 25 33 1 1/2” NPT Centrifugal
25 SQF-6 0 – 60 25 35 1 1/2” NPT Centrifugal
40 SQF-3 0 – 20 40 37 2” NPT Centrifugal
75 SQF-3 0 – 40 75 39 2” NPT Centrifugal


Helical Rotor Pump

Based on original pumping principles, the helical rotor pump uses a few, simple components for effective pumping in high head and low flow conditions.

Technology based on 30 years’ experience enables high flow in shallow water conditions. Stainless steel components give high wear resistance.
Centrifugal Pump

Stainless steel for long pump life.


Powerful carbon/ceramic bearing
system ensures extreme reliability.


Only one motor for the entire pump
range with built-in unique features.
A newly developed segmented stator
provides high efficiency.


The unique Grundfos micro frequency converter
ensures power transmission to the motor.


Maximum Power Point Tracking (MPPT)
means even and high system efficiency
regardless of power source.


Two-way communication between
interface box and pump eliminates the
needs for additional wires.


A wide voltage range enables the motor to operate
at any voltage between 30V and 300V DC or
90-240V AC, which makes installation and sizing
especially easy.

SQFlex – Energy Sources

In the middle of nowhere, the only things you can depend upon are air and daylight. The SQFlex pump is fully operational from only one or, for greater peace-of-mind, a combination of these energy sources. SQFlex Solar and Wind systems are reliable, low-mainteance and cost-effective. In addition, the systems are sustainable and totally environmentally sound.

Documentation for Download



SQ Flex Grundfos centrifugal or helical rotor quality system for about the cost of a diaphragm pump. The Grundfos SQ Flex pumping system can also be powered by a wind generator if you have the right site. The Whisper H-80 Waterpumper is the required generator. Features:

  • Up to 390 foot head applications
  • 30-300 VDC, or 90-240 VAC single-phase AC input
  • Permanent magnet high efficiency motor
  • Overload protection
  • Over temperature protection
  • Dry running protection
  • Maximum Power Point Tracking to optimize pump operation according to DC Power available
  • Power line communication with the CU200 (optional) to display operational conditions


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