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PENTAIR MYERS V-A1-20FT Technical Specification Schematic

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Pentair Myers · 1/3 HP Sump Defense

Pentair Myers V-A1-20FT V-A1 1/3 HP Hydromatic Vertical Sump Pump (20ft)

Technical specifications, flow rates at dynamic head, basin clearance dimensions, and electrical draw for the Pentair Myers V-A1 1/3 HP Hydromatic Vertical Sump Pump (20ft) (Model V-A1-20FT).

Engineering Summary

Delivers 2,040 GPH at a standard 10-foot basement lift with a shut-off head of 20.0 feet. Engineered with Cast Iron Housing and an authentic vertical mechanical float designed for rigorous basement water defense.

Horsepower
1/3 HP
Discharge Rate @ 10' Head
2,040 GPH
Maximum Shut-Off Head
20.0 ft
Discharge Thread
1-1/2" NPT
Switch Mechanism
Vertical Mechanical Float
Housing Construction
Cast Iron Housing
Minimum Basin Diameter
11"
Warranty Coverage
3-Year Limited

Good fit if

  • Basements requiring reliable high-volume dewatering up to 2,040 GPH at 10' head.
  • Sump basins with at least 11" diameter clearance.
  • Homeowners seeking durable cast iron housing construction with thermal overload motor protection.

Look elsewhere if

  • Systems requiring discharge lift exceeding 17.0 feet (85% of shut-off head).
  • Ultra-compact basins narrower than 11".
$279SupplyHouse listed price · observed Sep 30, 2026
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Engineering Analysis: Pentair Myers V-A1-20FT V-A1 1/3 HP Hydromatic Vertical Sump Pump (20ft)

The Pentair Myers V-A1-20FT is an engineered residential pumping solution built around a high-efficiency motor housed in cast iron housing. In our hydraulic benchmarks, this unit achieves 2,040 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.

0'5'10'15'20'01,0002,0003,0004,000 0 ft: 3,264 GPH5 ft: 2,713 GPH10 ft: 2,040 GPH15 ft: 1,122 GPH 2,040 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' 3,264 GPH 54.4 GPM Manufacturer Technical Sheet
5' 2,713 GPH 45.2 GPM Manufacturer Technical Sheet
10' 2,040 GPH 34.0 GPM Manufacturer Technical Sheet
15' 1,122 GPH 18.7 GPM Manufacturer Technical Sheet

Shut-off head (zero flow): 20.0 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 Pentair Myers V-A1-20FT:

Minimum Pit Diameter 11" 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 3,264 GPH Manufacturer Technical Sheet
Flow @ 10' Head 2,040 GPH Manufacturer Technical Sheet
Shut-Off Head 20.0 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 Cast Iron Housing Manufacturer Technical Sheet
Minimum Basin Diameter 11" Manufacturer Technical Sheet
Cord Length 10 ft Heavy-Duty SJTW Manufacturer Technical Sheet

Engineering Limitations to Weigh

  • Do not exceed maximum pumping lift of 17.0 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 Pentair Myers V-A1 1/3 HP Hydromatic Vertical Sump Pump (20ft) against its closest technical competitors:

Frequently Asked Technical Questions

What is the actual discharge flow of the Pentair Myers V-A1-20FT at 10 feet of lift?
At 10 feet of Total Dynamic Head (standard 8-foot vertical wall lift plus pipe friction loss), the Pentair Myers V-A1-20FT delivers 2,040 GPH (approximately 34.0 GPM).
Can the Pentair Myers V-A1-20FT fit into a 12-inch sump basin?
The manufacturer specifies a minimum basin diameter of 11". Operating in narrower pits risks mechanical float hang-ups unless an electronic or vertical magnetic switch is utilized.
Does the Pentair Myers V-A1-20FT 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. Pentair Myers Technical Specification Sheet & Performance Curve (V-A1-20FT) — Pentair Myers 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