Grundfos 15 SQE Submersible Well Pump

SQE is a 3-inch diameter deep well submersible pump for 3 in and larger wells, suitable for both continuous and intermittent operation in domestic water supply, light commercial service, irrigation and tank applications. SQE pumps are equipped with a Grundfos Smart Motor: like SQ they use a high-efficiency permanent-magnet motor, but they add the ability to communicate. The Smart Motor talks to the CU 302 control box through the power leads, so no additional wires run down the well. That communication provides constant pressure control and the ability to change the pump performance while the pump is installed in the well. The SQE motor enables continuously variable speed control from 3,000 to 10,700 rpm, so the pump can be set to any duty point between those two curves. The variable speed control facility requires the CU 302 control unit.

The pumps are protected against dry running. A value of Pcut-out ensures cut-out of the pump in case of lack of water in the borehole, thus preventing a burnout of the motor. Pcut-out is factory-set. The integrated protection of all motors prevents damage in case the voltage moves outside the permissible range: the pump will cut out if the voltage falls below 150 V or rises above 315 V, and the motor is automatically cut in again when the voltage returns within range. Therefore no extra protection relay is needed. Exposure of the pump to heavy load causes the current consumption to rise; the motor automatically compensates by reducing the speed to 3000 rpm, and further overload will lead to stop. If the rotor is prevented from rotating, this is automatically detected and the power supply is cut out. Consequently, no extra motor protection is needed.

The pump design features floating impellers that are not fastened to the shaft. Each impeller has its own tungsten carbide / ceramic bearing, and the construction and materials ensure high wear resistance to sand for long product life. The hydraulic pump components are polyamide reinforced with 30 % glass fiber; the hydraulic design provides for high pump efficiency resulting in low energy consumption. Starting up a pump with very low counter pressure involves the risk of the entire impeller stack being lifted, also called upthrust, which may cause breakdown of both pump and motor. A top bearing protects both pump and motor against upthrust, thus preventing breakdown during the critical start-up phase.

A built-in check valve with spring and low weight mean the pump may be installed vertically, horizontally or in any position in between, but it must not fall below the horizontal level in relation to the motor. For horizontal installation a flow sleeve is recommended, to ensure sufficient flow velocity past the motor for cooling and to prevent the motor and electronic unit from being buried in sand or mud.

With a CU 302 the system maintains a constant pressure within the maximum pump performance in spite of varying water consumption. The pressure is registered by the pressure sensor and transmitted to the CU 302, which adjusts the pump performance accordingly by changing the pump speed. When a tap is opened the pressure in the tank starts to drop; at a flow below roughly 1 gpm the pressure drops slowly and the pump starts when the tank is 7 psi below setpoint, running until it is 7 psi above setpoint — on/off operation. At a flow above roughly 1 gpm the pressure drops quickly, the pump starts immediately and holds a constant pressure. With no consumption the pump boosts to 7 psi above setpoint and stops after a few seconds. Because the pump follows demand rather than cycling between two switch settings, the installation uses a 2 gal diaphragm tank instead of a conventional pressure tank.

• Constant pressure control — with a CU 302 the pump holds your chosen setpoint from a trickle to full flow, so pressure does not sag when a second fixture opens.
• Continuously variable speed, 3,000 to 10,700 rpm — the duty point can be moved anywhere between the two curves, and changed with the pump still down the well.
• Electronic control and communication — GENIbus to the CU 302 over the power cable, Bluetooth to Grundfos GO at the control unit, with alarm and warning indication including dry running, overvoltage, overtemperature and overload.
• Dry-run protection — factory-set Pcut-out stops the pump when the borehole runs short of water, preventing motor burnout.
• Overvoltage and undervoltage protection — cuts out below 150 V and above 315 V and restarts automatically when supply returns to range. No protection relay needed.
• Overload protection — the motor reduces speed to 3000 rpm under heavy load, stops on further overload, and cuts power if the rotor is blocked. No separate motor protection needed.
• Overtemperature protection — a temperature sensor in the electronic unit cuts the motor out when temperature rises too high and cuts back in once it drops.
• Soft start — reduces starting current and gives smooth, steady acceleration, minimising wear on the pump and avoiding overloading the mains at start-up.
• High starting torque — high locked-rotor torque of the permanent magnet motor combined with few pump stages, and the starting reliability holds up at low supply voltage.
• Protection against upthrust — a top bearing protects pump and motor against impeller-stack lift during the critical start-up phase.
• Floating impellers — not fastened to the shaft, each with its own tungsten carbide / ceramic bearing, for high wear resistance to sand.
• 2-wire single-phase design — the CU 302 communicates over the same two power leads, so nothing extra runs down the well.
• Built-in check valve with spring and a 2.68 in pump diameter, 2.91 in including the cable guard, for 3 in and larger wells.
• Stainless steel exterior — AISI 304 outlet chamber, pump sleeve, cable guard, shaft and motor housing.

• Domestic water supply in single-family dwellings and seasonal homes not connected to municipal waterworks
• Light commercial water supply and small waterworks
• Irrigation systems
• Tank applications — liquid transfer, emptying or filling a tank, pumping from one tank to another
• Pressure boosting and groundwater lowering
• Maintaining a constant water table

SQE is normally installed with a CU 302 control unit, a pressure sensor and a 2 gal diaphragm tank for constant-pressure service. Without a CU 302 an SQE runs at maximum speed like an SQ on a conventional pressure switch and pressure tank, but the constant-pressure function and the variable-speed range are not available.

Type key. In 15 SQE05-70: 15 is rated gallons per minute, SQE is the type range (E for electronic communication), 05 is horsepower and -70 is total dynamic head in feet at rated flow.

Order by part number. 15 SQE05-70 — 96160189; 15 SQE05-110 — 96160190; 15 SQE07-150 — 96160191; 15 SQE07-180 — 96160192; 15 SQE10-220 — 96160193; 15 SQE10-250 — 96160194; 15 SQE15-290 — 96160195; 15 SQE15-330 — 93001434. The 1/2 HP models carry a second part number for the 100-115 V version: 15 SQE05-70 — 96160211; 15 SQE05-110 — 96160212.

Cable sizing. Maximum drop cable length in feet by copper wire size:

Accessories. CU 302 control unit with PSI sensor (UL) — product number 92817764; CU 302 without sensor, PSI (UL) — 92799799. SQ, SQE flow sleeve, complete — 98148594. SP, SQ, SQE wrench — 99588350. Cable kit, SQ SQE 14 AWG 5 ft NSF, motor model C — 97778332.

The free Grundfos HOME app gives you full control of your water system from an iOS or Android phone. Pair an SQE with a CU 302 control unit and the app reports pump information around the clock, sends alert notifications on important events so you can act before the water goes off, and carries a built-in watering calendar with an internal clock so irrigation routines run to schedule without a timer. Installer details are stored in the app, so whoever set the system up is one tap away.