Small Diameter, Big Results

Seven reasons to install the Grundfos 3-inch SQ submersible pump.

Looking for a submersible pump that can fit in restricted wells but is tough enough to meet the demands of your challenging applications? The Grundfos 3-inch SQ is unique in the market for its powerful operation and extensive range of built-in protection features, all packaged into a durable 3-inch design.

Launched by Grundfos in 1999, the SQ pump has 20 years of proven experience and reliability in the United States market. The SQ is available in five flow rate sizes and can deliver up to 39 gallons per minute and up to 780 feet of head.

Learn why the SQ is a smart choice for your next installation and why other water well contractors across the country use the Grundfos 3-inch SQ.

Powerful Motor Technology

The SQ’s pump technology and hydraulic design differ drastically from those of conventional 4-inch pumps. The SQ motor runs at up to 10,700 RPM, compared to traditional pumps that run at 3,450 RPM. The SQ also has a permanent magnet motor controlled by a built-in micro frequency converter, which changes single-phase input power into three-phase power. For this reason, the SQ has a simple 2-wire design yet operates as effectively as a conventional 3-wire motor.

A Durable Design That’s Easy to Install

Composed of stainless steel pump housing, the SQ pump features floating impellers and tungsten carbide/ceramic bearings. The design ensures high-wear resistance to sand while reducing the pump’s weight to less than 15 pounds—making installation simple. Most conventional 4-inch pumps weigh more than 25 pounds and can be challenging to install in restricted wells or applications with mineral buildup.

“The SQ is better to install because of the 3-inch diameter, and the pump weighs less than 15 pounds.”
Roger Powell, manager at Patuxent Pump & Well Inc.

No Dry-Run Callbacks

The SQ has built-in dry-run protection. When water vacates the pump, power consumption is automatically reduced. If this low power consumption remains for 5 seconds, the SQ stops. The motor will then attempt to restart every 5 minutes until water is restored to the pump. By contrast, traditional 4-inch submersible motors are unable to detect dry running and will continue to operate until excessive heat buildup trips a thermal overload or the pump fails.

Built-in Soft Start

The soft start feature in the SQ protects the system against water hammer and axial thrust on the drop pipe. This reduces wear on pump components and ensures reliable startup when voltage is low. The SQ uses a low starting current to reduce the electrical load, reaching nominal speed and current draw 2 to 3 seconds after startup through a smooth and steady acceleration. The SQ’s soft start does not sacrifice torque—starting torque exceeds that of conventional direct on-line 3-wire motors, which ramp up to maximum speed almost instantaneously.

“The soft start capability of the SQ is my favorite feature—you don’t have a pump slamming off and on all the time.”
Grant Floyd, installer at Wendell J. Lee Well Services Inc.

Over/Under Voltage Protection

The SQ protects against over/under voltage, operating between 150 volts and 280 volts with very little effect on pump performance. By comparison, a conventional 4-inch 230-volt motor can typically only operate within a range of 207 to 244 volts. When supply voltage drops below 180 volts, the SQ continues to operate at a slightly reduced speed to protect the motor. When it drops below 150 volts, the motor shuts down altogether. If it exceeds 280 volts, the SQ motor will shut down to protect itself. When the voltage returns to an acceptable level, the SQ will automatically restart. The SQ can also withstand voltage surges of up to 6000 volts.

“The voltage range on the SQ pump is amazing. It can go as low as 150 volts and all the way up to 280 volts.”
Travis Franklin, owner of A-1 Well & Pump Services

Thermal Protection

If a traditional 4-inch pump continues to operate when voltage supply is outside the normal range, it can affect the motor’s temperature,
potentially damaging the windings and reducing its lifespan. External motor protection devices for 4-inch pumps are an additional cost and must be manually reset to continue operation. The SQ can handle variable voltage and will restart automatically.

Lower Installation Cost

The SQ allows for the use of smaller gauge wire and a smaller than normal bladder or diaphragm tank. It also eliminates the need for an additional control box and motor protection devices, reducing total equipment cost and making installation quick and simple.

“The SQ is really cost effective. It saves us money and saves the homeowners money.”
Bill Schlotter, installer at Raab Well Drilling Inc.

Install the Grundfos SQ and experience the benefits a durable 3-inch submersible pump can deliver. Read more.