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LIBERTY PUMPS 457-25FT Technical Specification Schematic

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Liberty Pumps · 1/2 HP Sump Defense

Liberty Pumps 457-25FT 457 1/2 HP High-Flow Deep Pit Sump Pump (25ft)

Technical specifications, flow rates at dynamic head, basin clearance dimensions, and electrical draw for the Liberty Pumps 457 1/2 HP High-Flow Deep Pit Sump Pump (25ft) (Model 457-25FT).

Engineering Summary

Delivers 3,720 GPH at a standard 10-foot basement lift with a shut-off head of 34.0 feet. Engineered with Class 25 Cast Iron and an authentic vmf magnetically coupled float designed for rigorous basement water defense.

Horsepower
1/2 HP
Discharge Rate @ 10' Head
3,720 GPH
Maximum Shut-Off Head
34.0 ft
Discharge Thread
2" NPT
Switch Mechanism
VMF Magnetically Coupled 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 3,720 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 28.9 feet (85% of shut-off head).
  • Ultra-compact basins narrower than 14".
$409SupplyHouse listed price · observed Sep 30, 2026
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Engineering Analysis: Liberty Pumps 457-25FT 457 1/2 HP High-Flow Deep Pit Sump Pump (25ft)

The Liberty Pumps 457-25FT 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 3,720 GPH at 10 feet of Total Dynamic Head, operating well within standard residential basement parameters.

Actuation is controlled via an integrated vmf magnetically coupled 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 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.

0'5'10'15'20'25'02,0004,0006,000 0 ft: 5,952 GPH5 ft: 4,947 GPH10 ft: 3,720 GPH15 ft: 2,046 GPH20 ft: 744 GPH 3,720 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' 5,952 GPH 99.2 GPM Manufacturer Technical Sheet
5' 4,947 GPH 82.5 GPM Manufacturer Technical Sheet
10' 3,720 GPH 62.0 GPM Manufacturer Technical Sheet
15' 2,046 GPH 34.1 GPM Manufacturer Technical Sheet
20' 744 GPH 12.4 GPM Manufacturer Technical Sheet

Shut-off head (zero flow): 34.0 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 457-25FT:

Minimum Pit Diameter 14" clear diameter recommended for proper switch cycle operation.
Discharge Pipe Diameter 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 5,952 GPH Manufacturer Technical Sheet
Flow @ 10' Head 3,720 GPH Manufacturer Technical Sheet
Shut-Off Head 34.0 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 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 28.9 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 457-25FT 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 457-25FT delivers 3,720 GPH (approximately 62.0 GPM).
Can the Liberty Pumps 457-25FT 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 457-25FT 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 (457-25FT) — 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