Grundfos · 3 in Submersible Well Pump
15 SQ
Nominal 15 GPM 3 in submersible well pump with a permanent-magnet motor and built-in protection: 8 models from 1/2 to 1-1/2 HP, 75-355 ft of head at 15 GPM, 1-1/4 in NPT discharge. Two-wire: no control box.
15 GPM Rated Flow
1/2 to 1-1/2 HP
75-355 ft at 15 GPM
4-20 GPM Flow Range
2-Wire · No Control Box
3 in Min. Well
1-1/4 in NPT Discharge
115V or 230V 1Ph
Dry-Run, Voltage and Overload Protection
2.9 in Dia x 29.1-37.0 in L
11-16 lb Ship Weight
Overview
The Grundfos 15 SQ is a 3 in stainless steel well pump with a high-efficiency permanent-magnet motor and its electronics built in. It is a 2-wire pump: it runs straight from the breaker through a pressure switch, with no control box, capacitor or starter, and Grundfos puts the pump weight under 15 lb, so one person can handle it.
It is rated at 15 GPM, with 8 models from 1/2 to 1-1/2 HP for deeper settings. The pump fits a 3 in or larger well, so it also serves wells too narrow for a 4 in pump, and suits household supply, light commercial service, irrigation and tank applications.
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Built-in protection. Dry-run, over- and undervoltage (cuts out below 150 V and above 315 V and restarts by itself), overload, locked-rotor and over-temperature protection are built into the motor. No protection relay or starter needed.
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Soft start, no start limit. The motor ramps up in about 3 seconds and has no limit on starts or stops per hour, which also eases generator and light-circuit starting.
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Wide voltage window. Runs on 150 to 280 V supplies (230 V models), where a conventional 4 in motor needs 207 to 244 V.
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Sand-tolerant hydraulics. Floating impellers each run on their own tungsten carbide / ceramic bearing; a top bearing protects pump and motor against upthrust at start-up.
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Install it any way up. Vertical, horizontal or anywhere between, with a built-in spring check valve; use a flow sleeve when horizontal.
What Ships and What It Needs to Run
Included: the pump and its 3 in SQ motor, assembled, with a built-in check valve, plus a 5 ft, 14 AWG motor cable with plug that you press onto the motor socket and secure with four screws.
No control box needed. The SQ is 2-wire: connect it to the main breaker and start it with a pressure switch rated for the pump's current, with a pressure tank.
Never connect: a capacitor, a control box or an external frequency drive.
Drop cable, splice kit, pressure switch and tank: sized for your installation and ordered separately; the cable table is under Models & Performance. A replacement motor cable is on our Grundfos SQ and SQE Pump Accessories listing; you do not need one for a new pump.
Genuine Grundfos equipment, factory-new in original packaging — sold and supported by Watermain Supply, an independent industrial supplier.
Warranty
24 months from date of installation, but not more than 30 months from date of manufacture. In Grundfos's words, products are “warranted to the original user only to be free of defects in material and workmanship”; the full terms are in the installation and operating instructions on the Data Sheet tab.
Specifications
| Specification |
Value |
| Rated flow |
15 GPM nominal; working range 4-20 GPM |
| Horsepower |
1/2 to 1-1/2 HP |
| Supply |
1 x 100-115 V (1/2 HP only) or 1 x 200-240 V, 60 Hz; 2-wire plus ground |
| Motor |
MS 3 permanent-magnet motor with built-in electronics |
| Protection |
Dry run, overvoltage and undervoltage (cuts out below 150 V and above 315 V), overload, locked rotor, over-temperature |
| Starting |
Soft start, run-up maximum 3 seconds; no limit on starts or stops per hour |
| Motor cable |
3-wire, 14 AWG XLPE, 5 ft, with plug |
| Discharge |
1-1/4 in NPT |
| Well diameter |
3 in minimum |
| Setting depth |
Up to 500 ft below the static water level; at least 20 in below the pumping water level |
| Pumped liquid |
Clean water, pH 5 to 9, up to 86°F |
| Generator |
Output at least the motor input power (P1) plus 50% recommended, never less than P1 plus 10% |
Source: Grundfos SQ, SQE, SmartFlo and SP data booklet (North America, 60 Hz), technical data.
Models & Performance — Will It Do What You Need?
Pick a model whose head at your flow covers the pumping water level, the pressure you need at the surface (2.31 ft per PSI) and pipe friction. Then check the 30/50 table for what it delivers at your depth.
| Model |
HP |
0 GPM (Shut-off) |
3.9 GPM |
9.7 GPM |
15 GPM (Rated) |
19.3 GPM (Max) |
| 15 SQ05-70 |
1/2 |
117 |
114 |
104 |
75 |
43 |
| 15 SQ05-110 |
1/2 |
183 |
179 |
164 |
123 |
68 |
| 15 SQ07-150 |
3/4 |
242 |
237 |
216 |
164 |
94 |
| 15 SQ07-180 |
3/4 |
300 |
296 |
269 |
205 |
118 |
| 15 SQ10-220 |
1 |
361 |
355 |
323 |
246 |
141 |
| 15 SQ10-250 |
1 |
421 |
415 |
376 |
287 |
164 |
| 15 SQ15-290 |
1-1/2 |
481 |
474 |
430 |
328 |
186 |
| 15 SQ15-330 |
1-1/2 |
525 |
517 |
470 |
355 |
203 |
Total head in feet. The shut-off and flow columns are read from the Grundfos 60 Hz curves for the 15 SQ, SQE (SQ and SQE share one curve, the SQE at its 10,700 rpm top speed), digitized from the published curve charts in the Grundfos SQ, SQE, SmartFlo and SP data booklet, at the nearest published point and rounded down. The (Rated) column is the head Grundfos prints at 15 GPM in its system sizing matrix, verbatim; the number in the model name is a nominal figure and reads lower on some models. 1 ft of head = 0.433 PSI. Full curves are in the product images and on the Data Sheet tab.
What It Delivers on a 30/50 Pressure Switch
Output at 30 and 50 PSI · 1/2 to 3/4 HP · 4 models · depths 20 to 220 ft
GPM at 30 PSI (switch cut-in), by depth to water
| Model |
20 ft |
60 ft |
80 ft |
120 ft |
160 ft |
180 ft |
220 ft |
| 15 SQ05-70 |
12.8 |
— |
— |
— |
— |
— |
— |
| 15 SQ05-110 |
18 |
14.5 |
11.9 |
— |
— |
— |
— |
| 15 SQ07-150 |
— |
17.5 |
16.3 |
12.9 |
6.6 |
— |
— |
| 15 SQ07-180 |
— |
19 |
18.1 |
16.1 |
13.4 |
11.9 |
6.5 |
GPM at 50 PSI (switch cut-out), by depth to water
| Model |
20 ft |
60 ft |
80 ft |
120 ft |
160 ft |
180 ft |
220 ft |
| 15 SQ05-70 |
— |
— |
— |
— |
— |
— |
— |
| 15 SQ05-110 |
13.8 |
6.2 |
— |
— |
— |
— |
— |
| 15 SQ07-150 |
17 |
14.1 |
12.3 |
4.8 |
— |
— |
— |
| 15 SQ07-180 |
18.7 |
16.8 |
15.7 |
12.8 |
9 |
4.8 |
— |
Output at 30 and 50 PSI · 1 to 1-1/2 HP · 4 models · depths 40 to 400 ft
GPM at 30 PSI (switch cut-in), by depth to water
| Model |
40 ft |
80 ft |
140 ft |
200 ft |
240 ft |
280 ft |
400 ft |
| 15 SQ10-220 |
— |
19.2 |
16.8 |
13.8 |
11.1 |
6 |
— |
| 15 SQ10-250 |
— |
— |
18.2 |
15.8 |
13 |
10.3 |
— |
| 15 SQ15-290 |
— |
— |
18.9 |
17.2 |
15.9 |
14.3 |
5.1 |
| 15 SQ15-330* |
— |
— |
19 |
17.5 |
16.5 |
15 |
9.5 |
GPM at 50 PSI (switch cut-out), by depth to water
| Model |
40 ft |
80 ft |
140 ft |
200 ft |
240 ft |
280 ft |
400 ft |
| 15 SQ10-220 |
18.9 |
17.4 |
14.6 |
10.3 |
4.3 |
— |
— |
| 15 SQ10-250 |
— |
18.5 |
16.4 |
13.7 |
11.4 |
7.8 |
— |
| 15 SQ15-290 |
— |
19.2 |
17.7 |
15.6 |
14 |
12 |
— |
| 15 SQ15-330* |
— |
— |
18 |
16 |
15 |
13.5 |
4 |
From the Grundfos 3 in SQ sizing charts (pp. 40-41), verbatim: gallons per minute at the pressure shown and the depth to pumping water level. Riser and pipe friction are not included. A dash means Grundfos prints no figure: on the shallow side the flow is past the chart range, on the deep side the pump cannot reach that pressure. * 15 SQ15-330: Grundfos prints no sizing chart for this model, so its row is calculated, not printed: the flow where the published curve meets the depth plus 69 ft (30 PSI) or 116 ft (50 PSI), interpolated between published points and rounded down to 0.5 GPM.
Drop Cable Size
Drop cable size by distance · copper, 60 Hz
| Volts |
HP |
Amps |
14 AWG |
12 AWG |
10 AWG |
8 AWG |
6 AWG |
4 AWG |
2 AWG |
| 115 |
1/2 |
12 |
140 |
220 |
360 |
550 |
880 |
1390 |
2260 |
| 230 |
1/2 |
5.2 |
640 |
1000 |
1660 |
2250 |
4060 |
— |
— |
| 230 |
3/4 |
8.4 |
400 |
620 |
1030 |
1580 |
2510 |
3970 |
— |
| 230 |
1 |
11.2 |
300 |
460 |
770 |
1190 |
1890 |
2980 |
4850 |
| 230 |
1-1/2 |
12 |
280 |
430 |
720 |
1110 |
1760 |
2780 |
4530 |
Maximum length in feet from the motor to the service entrance, copper wire, 9% voltage drop, from the Grundfos SQ, SQE installation and operating instructions and data booklet. A dash means not listed.
Before You Buy — The Limits That Decide the Fit
| Check |
What to confirm |
| Well size |
3 in or larger casing |
| Water |
Clean water, pH 5 to 9, up to 86°F |
| Setting |
No deeper than 500 ft below the static water level, and at least 20 in below the pumping water level |
| Power |
1/2 HP models come in 115 V or 230 V versions (different part numbers, not field-convertible); 3/4 HP and up are 230 V only |
| Wiring |
A pressure switch rated for the pump's maximum current (motor nameplate). Never a capacitor, control box or external drive |
| Horizontal install |
Use the SQ/SQE flow sleeve (on our Grundfos SQ and SQE Pump Accessories listing) to keep water moving past the motor |
| Generator |
At least the motor input power plus 50% (minimum plus 10%) |
Materials of Construction
| Part |
Material |
| Pump sleeve, outlet chamber, cable guard |
AISI 304 stainless steel |
| Impellers, chambers, guide vanes, valve casing |
Polyamide (30% glass-fibre reinforced) |
| Impeller bearings |
Tungsten carbide / ceramic |
| Shaft |
AISI 304 stainless steel |
| Valve seat, seals |
NBR rubber |
| Motor stator, rotor, top cover |
AISI 304 stainless steel |
| Motor bearings |
Silicon carbide / tungsten carbide (coated); carbon thrust bearing |
Source: Grundfos SQ, SQE, SmartFlo and SP data booklet, construction.
