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S420 Series

Accepts 4-20mA analog input signal


  • Leak detection
  • Backup pump capability
  • Remote start or stop
  • LED Indicators
  • Three dedicated output relays
  • 2 year warranty

Flow Rate Output Control with 4-20mA Analog Input Signal or Manual Adjustment

The S420 Series (watch video) variable speed peristaltic metering pumps dose liquid solutions in direct proportion to a 4-20mA analog input signal.  The operator can scale the pump’s response to the signal from 25% to 100% by the potentiometer on the control pad. When operated in the manual mode the maximum flow rate output is adjustable from 5% to 100%.

The pump’s ability to accept an incoming 4-20mA analog signal to pace the pump makes the S420 well suited for use with water treatment controls including pH and ORP monitors to maintain proper water chemistry and treatment of effluent discharge water. Common installations include industrial and municipal wastewater treatment facilities or municipalities that supply potable water to residential and commercial sites requiring well or surface water treatment.  For the treatment of process water, the S420 can inject solutions such as disinfectants, oxidizing agents, acids, and alkaline.  Please check available chemical resistant charts for compatibility.

Additional Applications

  • Injection of liquid biocides in cooling towers for prevention of Legionnaires disease
  • Corrosion, scale, and algae control on plumbing fixtures and water supply equipment
  • Metering additives specific to a manufacturing process
  • pH control for process water or metal plating discharge water


The S420 offers practical value-added features.  The leak detection feature has a dedicated output relay and an LED status indicator on the control pad. When a leak is detected, the pump stops operating, provides an output signal and the Leak LED illuminates. The pump offers back-up capability to the primary pump to maintain operation in critical applications. When activated, the primary pump transfers operation seamlessly to the back-up pump.  There are additional LED indicators that communicate the status of the pump.

Built for heavy-duty applications and challenging environments the pump has a brushless DC motor with ball bearing support and a rugged polycarbonate enclosure with NEMA 4X rating. Tube replacement is without tools and is standard on all Stenner metering pumps. The pump heads and tubes are interchangeable to convert one model to another without having to purchase a new pump. The S420 series has a 2 year warranty.

The series is categorized by three item number prefixes, S34, S44, & S54.  Pumps beginning with S34 have six flow rate outputs ranging from up to 40 gallons per day with operating pressures to 100 psi maximum and up to 85 gallons per day with operating pressures to 25 psi maximum.  Pumps beginning with S44 have two flow rate outputs of 60 gallons per day with operating pressures to 100 psi maximum and of 150 gallons per day with operating pressures to 25 psi maximum. Pumps beginning with S54 have two flow rate outputs of 125 gallons per day with operating pressures to 100 psi maximum and of 315 gallons per day with operating pressures to 25 psi maximum.

How It Works

The pump flow rate output is adjusted by an incoming 4-20mA analog input signal which can be scaled by the potentiometer on the control pad. The maximum flow rate output is scalable from 25% to 100%. When in manual mode the flow rate output is adjustable from 5% to 100%.

Stenner Peristaltic Pump Advantages

  • Self-priming against max. working pressure; foot valve not required
  • Solutions do not contact moving parts
  • Pump head requires no valves, allows for easy maintenance
  • Does not lose prime or vapor lock
  • Pumps off-gassing solutions and can run dry.
  • Output volume is not affected by backpressure.
  • SImple tube replacement  


Flow Rate Outputs

S34 and S44 Models
Pump Tube Turndown
per Day
per Hour
per Hour
per Minute
per Day
per Hour
per Hour
per Minute
25 psi (1.7 bar) max. Approximate Output @ 50/60Hz
S3403 3 100:1 20:1 40.0 1.67 213.0 3.56 151.0 6.31 6309.0 105.0
S3404 4 100:1 20:1 60.0 2.50 320.0 5.33 227.0 9.46 9464.0 158.0
S3405 5 100:1 20:1 85.0 3.54 453.0 7.56 322.0 13.41 13407.0 223.0
5X 100:1 20:1 150.0 6.25 800.0 13.33 568.0 23.66 23659.0 394.0
S5V5G 5G 100:1 20:1 315.0 13.13 1680.0 28.0 1192.0 49.68 49684.0 828.0
100 psi (6.9 bar) max. Approximate Output @ 50/60Hz
S3401 1 100:1 20:1 5.0 0.21 27.0 0.44 19.0 0.79 789.0 13.0
S3402 2 100:1 20:1 17.0 0.71 91.0 1.51 64.0 2.68 2681.0 45.0
S3407 7 100:1 20:1 40.0 1.67 213.0 3.56 151.0 6.31 6309.0 105.0
S447X 7X 100:1 20:1 60.0 2.50 320.0 5.33 227.0 9.46 9464.0 158.0
S5V7G 7G 100:1 20:1 125.0 5.21 667.0 11.11 473.0 19.72 19716.0 329.5
NOTICE: The information within the charts above is solely intended for use as a guide. The output data is an approximation based on pumping water under a controlled testing environment. Many variables can affect the output of the pump. Stenner Pump Company recommends that all metering pumps undergo field calibration by means of analytical testing to confirm their outputs

Technical Data


Flow Rate Output Control 4-20mA analog input signal or manual
Reproducibility +/- 2%
Maximum Working Pressure 25 psi (1.7 bar), 100 psi (6.9 bar)
Maximum Operating Temperature 104°F (40°C)
Maximum Suction Lift 25 ft (7.6 m) vertical lift, based on water
Motor Type Brushless DC motor
Shaft RPM (average maximum) 45
Duty Cycle Continuous
Maximum Viscosity 1500 centipoise
Motor Voltage (Amp Draw) 120V 60Hz 1PH (0.6), 230V 50Hz I PH  (0.3), 230V 50Hz 1PH (0.3)
Power Cord Type 120V 60Hz, 230V 60Hz: SJTOWA, 230V 60 Hz SJTOWA, 230V 50Hz: H05RN-F
Power Cord Plug End 120V 60Hz 5-15P, 230V 60Hz 6-15P,
230V 50Hz CEE7/7
Cord Length 6 ft (1.8 m)
Classification Indoor/Outdoor


Materials of Construction
All Housings Polycarbonate
Pump Tube (S34) Santoprene®*(FDA approved), or Versilon®** 
Pump Tube (S44, S54) Santoprene®*(FDA approved)
Check Valve Duckbill (S34) Santoprene®*  (FDA approved), or Pellethane®† 
Ball Check Valve Components (S44, S54) Ceramic ball (FDA approved); Tantalum spring; FKM seat & O-ring OR
Ceramic ball (FDA approved); Stainless steel spring; EPDM seat; Santoprene®* O-ring
Pump Head Rollers (S34, S44) Polyethylene
Pump Head Rollers (S54) Polycarbonate
Roller Bushings (S34, S44) Oil impregnated bronze
Roller Ball Bearings (S54) Stainless steel
Suction/Discharge Tubing
and Ferrules
Polyethylene (FDA approved)
Tube & Injection Fittings PVC or Polypropylene (both NSF listed)
Connecting Nuts PVC or Polypropylene (both NSF listed)
3/8″ Adapter (S34) PVC or Polypropylene (both NSF listed)
Suction Line Strainer and Cap PVC or Polypropylene (both NSF listed); ceramic weight
All Fasteners Stainless steel
Pump Head Latches (S34) Polypropylene
Pump Head Thumbscrews (S44, S54) Stainless steel and PVC
Pump Head Support & Transition Sleeve (S44, S54) Santoprene®*
Tube Pull (S4V, S5V) PVC
Leak Detect Components (S34) Hastelloy®††
Leak Detect Components (S44, S54) Hastelloy®†† and stainless steel

*    Santoprene® is a trademark of Celanese International Corporation.
**  Versilon® is a registered trademark of Saint-Gobain Performance Plastics.
†   Pellethane® is a registered trademark of Lubrizol Advanced Materials, Inc.
†† Hastelloy® is a registered trademark of Haynes International, Inc.



Agency Listings

Listings vary by model.

Pump Dimensions

S34 Model

S44 Model

Box Dimensions

14 x 9 x 10 in. (35 x 23 x 24 cm)

Shipping Weight

9 lbs (3.7 kg)


S54 Model

Box Dimensions

16 x 13 x 14 in. (41 x 33 x 35 cm)

Shipping Weight

14 lbs (6.3 kg)

Dimensions & weight

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