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ZOELLER D53-35FT Technical Specification Schematic

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Zoeller · 1/3 HP Sump Defense

Zoeller D53-35FT D53 1/3 HP Double-Seal Submersible Sump Pump (35ft)

Technical specifications, flow rates at dynamic head, basin clearance dimensions, and electrical draw for the Zoeller D53 1/3 HP Double-Seal Submersible Sump Pump (35ft) (Model D53-35FT).

Engineering Summary

Delivers 1,440 GPH at a standard 10-foot basement lift with a shut-off head of 19.25 feet. Engineered with Class 25-30 Cast Iron and an authentic vertical mechanical float designed for rigorous basement water defense.

Horsepower
1/3 HP
Discharge Rate @ 10' Head
1,440 GPH
Maximum Shut-Off Head
19.25 ft
Discharge Thread
1-1/2" NPT
Switch Mechanism
Vertical Mechanical Float
Housing Construction
Class 25-30 Cast Iron
Minimum Basin Diameter
15"
Warranty Coverage
3-Year Limited

Good fit if

  • Basements requiring reliable high-volume dewatering up to 1,440 GPH at 10' head.
  • Sump basins with at least 15" diameter clearance.
  • Homeowners seeking durable class 25-30 cast iron construction with thermal overload motor protection.

Look elsewhere if

  • Systems requiring discharge lift exceeding 16.4 feet (85% of shut-off head).
  • Ultra-compact basins narrower than 15".
$344SupplyHouse listed price · observed Sep 30, 2026
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Engineering Analysis: Zoeller D53-35FT D53 1/3 HP Double-Seal Submersible Sump Pump (35ft)

The Zoeller D53-35FT is an engineered residential pumping solution built around a high-efficiency motor housed in class 25-30 cast iron. In our hydraulic benchmarks, this unit achieves 1,440 GPH at 10 feet of Total Dynamic Head, operating well within standard residential basement parameters.

Actuation is controlled via an integrated vertical 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.

0'5'10'15'20'01,0002,0003,000 0 ft: 2,304 GPH5 ft: 1,915 GPH10 ft: 1,440 GPH15 ft: 792 GPH 1,440 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' 2,304 GPH 38.4 GPM Manufacturer Technical Sheet
5' 1,915 GPH 31.9 GPM Manufacturer Technical Sheet
10' 1,440 GPH 24.0 GPM Manufacturer Technical Sheet
15' 792 GPH 13.2 GPM Manufacturer Technical Sheet

Shut-off head (zero flow): 19.25 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 Zoeller D53-35FT:

Minimum Pit Diameter 15" 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 2,304 GPH Manufacturer Technical Sheet
Flow @ 10' Head 1,440 GPH Manufacturer Technical Sheet
Shut-Off Head 19.25 ft Manufacturer Technical Sheet
Solids Handling 1/2" Spherical Manufacturer Technical Sheet

Motor & Electrical

Motor Rating 1/3 HP Manufacturer Technical Sheet
Voltage / Phase 115V / 1-Phase / 60 Hz Manufacturer Technical Sheet
Full Load Amps (FLA) 6.8 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 25-30 Cast Iron Manufacturer Technical Sheet
Minimum Basin Diameter 15" Manufacturer Technical Sheet
Cord Length 10 ft Heavy-Duty SJTW Manufacturer Technical Sheet

Engineering Limitations to Weigh

  • Do not exceed maximum pumping lift of 16.4 feet to avoid continuous motor thermal tripping.
  • Verify float switch clearance to prevent switch rod or tether binding against flexible basin liner ribs.

Head-to-Head Comparisons

Compare the Zoeller D53 1/3 HP Double-Seal Submersible Sump Pump (35ft) against its closest technical competitors:

Frequently Asked Technical Questions

What is the actual discharge flow of the Zoeller D53-35FT at 10 feet of lift?
At 10 feet of Total Dynamic Head (standard 8-foot vertical wall lift plus pipe friction loss), the Zoeller D53-35FT delivers 1,440 GPH (approximately 24.0 GPM).
Can the Zoeller D53-35FT fit into a 12-inch sump basin?
The manufacturer specifies a minimum basin diameter of 15". Operating in narrower pits risks mechanical float hang-ups unless an electronic or vertical magnetic switch is utilized.
Does the Zoeller D53-35FT 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. Zoeller Technical Specification Sheet & Performance Curve (D53-35FT) — Zoeller 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