Head-to-Head Comparison · 1/3 HP Class
Liberty Pumps 257 1/3 HP Cast Iron Sump Pump vs. Superior Pump 91330 1/3 HP Thermoplastic Sump Pump (10ft)
Engineering comparison between the Liberty Pumps 257 1/3 HP Cast Iron Sump Pump and Superior Pump 91330 1/3 HP Thermoplastic Sump Pump (10ft). Flow curves, switch durability, and technical verdict.
91330 1/3 HP Thermoplastic Sump Pump (10ft)
The Liberty Pumps 257 1/3 HP Cast Iron Sump Pump delivers 2,040 GPH at 10' head compared to 1,440 GPH for the Superior Pump 91330 1/3 HP Thermoplastic Sump Pump (10ft). If your basement requires maximum flow throughput, the Liberty Pumps holds the hydraulic advantage. For tight sump pits, compare the minimum basin clearances: 10" vs 10".
Specification Comparison Matrix
| Specification | Liberty Pumps 257 1/3 HP Cast Iron Sump Pump | Superior Pump 91330 1/3 HP Thermoplastic Sump Pump (10ft) | Advantage |
|---|---|---|---|
| Discharge Flow @ 10' Head | 2,040 GPH | 1,440 GPH | Liberty Pumps +600 GPH |
| Shut-Off Head | 21.0 ft | 26.0 ft | Superior Pump +5.0 ft |
| Switch Mechanism | VMF Magnetically-Coupled Vertical Float | Vertical Mechanical Float | Vertical Clearance |
| Housing Material | Class 25 Cast Iron | Corrosion Proof Thermoplastic | Thermal Heat Sink |
| Minimum Basin Diameter | 10" | 10" | Basin Fit |
| List Price | $264.00 | $89.00 | Lower Initial Cost |
Choose 257 1/3 HP Cast Iron Sump Pump If:
- You require 2,040 GPH discharge capacity at standard 10' head.
- Your installation prioritizes Class 25 Cast Iron for continuous motor heat dissipation.
- You prefer the VMF Magnetically-Coupled Vertical Float switch mechanism.
Choose 91330 1/3 HP Thermoplastic Sump Pump (10ft) If:
- You need 1,440 GPH flow capacity at 10' dynamic head.
- Your sump pit accommodates a 10" clearance footprint.
- You favor the Vertical Mechanical Float actuation design.
Hydraulic Performance & Head Sizing
When operating at 10 feet of Total Dynamic Head, the Liberty Pumps 257 delivers 2,040 GPH versus 1,440 GPH for the Superior Pump 91330-10FT. Pumping capacity curves indicate that both models handle standard residential foundation drainage effortlessly.
Switch Technology & Pit Clearance
The Liberty Pumps employs a VMF Magnetically-Coupled Vertical Float requiring a 10" pit, whereas the Superior Pump utilizes a Vertical Mechanical Float suited for basins with at least 10" clearance. Ensuring your pit allows uninhibited float movement is essential to preventing switch hang-ups.