Commercial Grade Digital Meters GPI

(Was Model 31704A) (Was Model 31804N)

Meter Type
Commercial Grade Digital Turbine Flow Meter, battery powered that displays rate of flow and totals.
How It Works
Magnetic pulses are picked up by a coil. The computer converts the pulses into a flow rate and totals.
Standard Features

  • Rate of Flow, 2 Totals (1 Resettable Batch, 1 Cumulative)
  • User Configurable to GPM, LPM or any Unit of Measure
  • Factory Calibrated for 1.0 Specific Gravity
  • Field Calibratable for fluids greater than 1.0 Specific Gravity
  • Digital Display with 6 Digits Starting at 0.01 (floating decimal)
  • Totals Maximum of 99,999,999
  • Powered by (2) 1.5V AAA Alkaline Batteries (2-year life)
  • Factory Calibration Certificate supplied with each meter
  • Aluminum Body suitable for Fuel, Diesel, Petroleum Based Liquids or other suitable applications
  • Nylon Body suitable for Water and Non-Aggressive Chemicals or other suitable applications
  • 1 Year Limited Warranty
A025 (Low Flow)A100A200N025 (Low Flow)N100
CONNECTIONS (Standard)1" NPT (Female)1" NPT (Female)2" NPT (Female)1" NPT (Female)1" NPT (Female)
FLOW RANGE0.3 - 3 GPM (1 - 11 LPM)3 - 50 GPM (11 - 190 LPM)30 - 300 GPM (114 - 1135 LPM)0.3 - 3 GPM (1 - 11 LPM)3 - 50 GPM (11 - 190 LPM)
ACCURACY± 5% depending on installation and fluid± 1.5% of reading± 1.5% of reading± 5% depending on installation and fluid± 1.5% of reading
REPEATABILITY± 1%± 0.2% of reading± 0.2% of reading± 1%± 0.2% of reading
PRESSURE RATING300 PSIG (21 Bar)300 PSIG (21 Bar)300 PSIG (21 Bar)150 PSIG (10.2 Bar)150 PSIG (10.2 Bar)
Meter with Local Display*0°F to 129/140°F (-18°C to 54/60°C)0°F to 129/140°F (-18°C to 54/60°C)0°F to 129/140°F (-18°C to 54/60°C)0°F to 129/140°F (-18°C to 54/60°C)0°F to 129/140°F (-18°C to 54/60°C)
Meter with Remote Display-40°F to 250°F (-40°C to 121°C)-40°F to 250°F (-40°C to 121°C)-40°F to 250°F (-40°C to 121°C)-40°F to 250°F (-40°C to 121°C)-40°F to 250°F (-40°C to 121°C)
PRESSURE DROP (AT FULL CAPACITY)2 PSIG (0.14 Bar)5 PSIG (0.34 Bar)7 PSI G (0.48 Bar)2 PSI G (0.14 Bar)5 PSI G (0.34 Bar)
MAXIMUM VISCOSITY100 cps100 cps100 cps100 cps100 cps
TYPICAL K-FACTOR (Pulses/Gal., Pulses/Lit.)2200 PPG / 581 PPL730 PPG / 193 PPL72 PPG / 19 PPL2200 PPG / 581 PPL730 PPG / 193 PPL
FREQUENCY RANGE11 - 110 Hz36.5 - 608.3 Hz36 - 360 Hz11 - 110 Hz36.5 - 608.3 Hz
(125 Microns)
35 Mesh (500 Microns)35 Mesh (500 Microns)120 Mesh
(125 Microns)
35 Mesh (500 Microns)
Minimum Upstream20" (508mm)20" (508mm)40" (1016mm)20" (508mm)20" (508mm)
Minimum Downstream5" (127mm)5" (127mm)10" (254mm)5" (127mm)5" (127mm)
Desired Upstream40" (1016mm)40" (1016mm)80" (2032mm)40" (1016mm)40" (1016mm)
Desired Downstream10" (254mm)10" (254mm)20" (508mm)10" (254mm)10" (254mm)
ShaftTungsten CarbideTungsten CarbideTungsten CarbideTungsten CarbideTungsten Carbide
Signal GeneratorFerriteFerriteFerriteFerriteFerrite
Retaining Rings316 Stainless Steel316 Stainless Steel316 Stainless Steel316 Stainless Steel316 Stainless Steel
CONN. TO CONN. LENGTH4" (101.6mm)4" (101.6mm)6" (152.4mm)4" (101.6mm)4" (101.6mm)

* Display rating for Safe Area is 140°F and for Hazardous Area is 129°F



  • Field programmable for Gallons or Liters
  • Quarts, Cubic Feet, Barrels, Cubic Cent., Ounces
  • Rates per Minute, Hour or Day
  • ISO Connections
  • BSPP Connections (Aluminum 1” Only)
  • N.I.S.T. Flow Certificate

Please contact our Sales Dept. for options
Replacement Parts

Optional Accessories

Alternate Meters

Application Notes

  • Saturated Steam Service: Not acceptable
  • Potable Water: Not acceptable (See Series GPI- QSE)
  • Vacuum Service: Not acceptable
  • Gaseous Service: Not acceptable
  • General Non-Suitable Services: Not acceptable for deionized (DI) or ultra-pure water applications. Aluminum is not recommended for water applications. Not suitable for medias with varying viscosities.
  • Installation: Hand tighten Nylon Bodies. Limit display’s exposure to sun.
  • Corrosion: Before ordering, verify all materials of our flow meters are compatible with the service media(s), intermittently used cleaners, the environment, and cleaning processes in conjunction with the temperatures and pressures of the application(s) and future applications. John C. Ernst Co. does not make chemical compatibility recommendations. Compatibility is the responsibility of the user and/or specifying party.

Model Number Matrixa
Model Number Matrix