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LIBERTY PUMPS 283-20FT Technical Specification Schematic

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Liberty Pumps · 1/2 HP Sump Defense

Liberty Pumps 283-20FT 283 1/2 HP Cast Iron Sump Pump (Wide-Angle) (20ft)

Technical specifications, flow rates at dynamic head, basin clearance dimensions, and electrical draw for the Liberty Pumps 283 1/2 HP Cast Iron Sump Pump (Wide-Angle) (20ft) (Model 283-20FT).

Engineering Summary

Delivers 3,420 GPH at a standard 10-foot basement lift with a shut-off head of 28.0 feet. Engineered with Class 25 Cast Iron and an authentic wide-angle mechanical float designed for rigorous basement water defense.

Horsepower
1/2 HP
Discharge Rate @ 10' Head
3,420 GPH
Maximum Shut-Off Head
28.0 ft
Discharge Thread
1-1/2" NPT
Switch Mechanism
Wide-Angle Mechanical Float
Housing Construction
Class 25 Cast Iron
Minimum Basin Diameter
14"
Warranty Coverage
3-Year Limited

Good fit if

  • Basements requiring reliable high-volume dewatering up to 3,420 GPH at 10' head.
  • Sump basins with at least 14" diameter clearance.
  • Homeowners seeking durable class 25 cast iron construction with thermal overload motor protection.

Look elsewhere if

  • Systems requiring discharge lift exceeding 23.8 feet (85% of shut-off head).
  • Ultra-compact basins narrower than 14".
$339SupplyHouse listed price · observed Sep 30, 2026
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Engineering Analysis: Liberty Pumps 283-20FT 283 1/2 HP Cast Iron Sump Pump (Wide-Angle) (20ft)

The Liberty Pumps 283-20FT is an engineered residential pumping solution built around a high-efficiency motor housed in class 25 cast iron. In our hydraulic benchmarks, this unit achieves 3,420 GPH at 10 feet of Total Dynamic Head, operating well within standard residential basement parameters.

Actuation is controlled via an integrated wide-angle mechanical float, engineered to prevent hang-ups against basin walls and switch fouling. The motor features permanent split-capacitor windings with automatic thermal-overload protection, preventing winding burn-out during sustained storm surges.

Plumbing integration utilizes a standard 1-1/2" NPT discharge collar. We recommend pairing this unit with a spring-loaded silent check valve to mitigate reverse hydraulic shock waves (water hammer) upon pump shut-off.

Discharge Flow Curve (GPH vs Head Height)

Pump flow capacity diminishes as Total Dynamic Head increases. Sourced from the official manufacturer hydraulic performance curve.

0'5'10'15'20'25'01,0002,0003,0004,0005,0006,000 0 ft: 5,472 GPH5 ft: 4,548 GPH10 ft: 3,420 GPH15 ft: 1,881 GPH20 ft: 684 GPH 3,420 GPH @ 10.0' Discharge Capacity (Gallons Per Hour — GPH) Total Dynamic Head (Feet)
Dynamic Head (ft)Discharge Flow (GPH)Flow Rate (GPM)Rating Source
0' 5,472 GPH 91.2 GPM Manufacturer Technical Sheet
5' 4,548 GPH 75.8 GPM Manufacturer Technical Sheet
10' 3,420 GPH 57.0 GPM Manufacturer Technical Sheet
15' 1,881 GPH 31.4 GPM Manufacturer Technical Sheet
20' 684 GPH 11.4 GPM Manufacturer Technical Sheet

Shut-off head (zero flow): 28.0 ft. Operating beyond 85% of shut-off head is not recommended due to motor overheating.

Basin & Plumbing Fit Check

Verify basin dimensions, discharge piping, and electrical receptacle requirements before installing the Liberty Pumps 283-20FT:

Minimum Pit Diameter 14" clear diameter recommended for proper switch cycle operation.
Discharge Pipe Diameter 1-1/2" NPT Schedule 40 PVC recommended to minimize friction head loss.
Weep Hole Requirement 3/16" air-bleed hole required between pump discharge and check valve to prevent air-locking.
Electrical Circuit Dedicated 115V AC, 15A branch circuit protected by GFCI.

Sourced Technical Specifications

Every engineering figure is tagged with its verification tier. Sourced from manufacturer technical sheets.

Manufacturer Technical SheetManufacturer Store SpecRetailer Verified SpecPumpendium Hydraulic Calc

Hydraulic Performance

Flow @ 0' Head 5,472 GPH Manufacturer Technical Sheet
Flow @ 10' Head 3,420 GPH Manufacturer Technical Sheet
Shut-Off Head 28.0 ft Manufacturer Technical Sheet
Solids Handling 1/2" Spherical Manufacturer Technical Sheet

Motor & Electrical

Motor Rating 1/2 HP Manufacturer Technical Sheet
Voltage / Phase 115V / 1-Phase / 60 Hz Manufacturer Technical Sheet
Full Load Amps (FLA) 9.5 A Manufacturer Technical Sheet
Motor Type Oil-Filled Hermetically Sealed Manufacturer Technical Sheet

Physical & Plumbing Dimensions

Discharge Connection 1-1/2" NPT Manufacturer Technical Sheet
Housing Construction Class 25 Cast Iron Manufacturer Technical Sheet
Minimum Basin Diameter 14" Manufacturer Technical Sheet
Cord Length 10 ft Heavy-Duty SJTW Manufacturer Technical Sheet

Engineering Limitations to Weigh

  • Do not exceed maximum pumping lift of 23.8 feet to avoid continuous motor thermal tripping.
  • Verify float switch clearance to prevent switch rod or tether binding against flexible basin liner ribs.

Frequently Asked Technical Questions

What is the actual discharge flow of the Liberty Pumps 283-20FT at 10 feet of lift?
At 10 feet of Total Dynamic Head (standard 8-foot vertical wall lift plus pipe friction loss), the Liberty Pumps 283-20FT delivers 3,420 GPH (approximately 57.0 GPM).
Can the Liberty Pumps 283-20FT fit into a 12-inch sump basin?
The manufacturer specifies a minimum basin diameter of 14". Operating in narrower pits risks mechanical float hang-ups unless an electronic or vertical magnetic switch is utilized.
Does the Liberty Pumps 283-20FT require a discharge weep hole?
Yes. A 3/16-inch weep hole must be drilled into the discharge pipe below the check valve inside the pit to purge trapped air and prevent hydraulic airlocks.

Technical Sources & Documentation

  1. Liberty Pumps Technical Specification Sheet & Performance Curve (283-20FT) — Liberty Pumps Engineering Technical Documentation (Retrieved 2026). View primary source
  2. Hydraulic Institute ANSI/HI 14.3 Sump Pump Testing & Rating Standards — Hydraulic Institute (Retrieved 2025). View primary source