Stenner S420 Series 4-20mA Controlled Peristaltic Metering Pumps
The Stenner S420 Series is a variable-speed peristaltic metering pump designed for applications requiring chemical dosing proportional to a 4-20mA analog control signal. By automatically adjusting pump output in response to process control equipment, the S420 provides accurate chemical feed for water treatment, wastewater treatment, industrial processes, and commercial aquatic systems.
Available in S34, S44, and S54 models, the S420 Series delivers outputs up to 315 GPD at 25 PSI and 125 GPD at 100 PSI, making it suitable for both low-volume and higher-capacity metering applications.
4-20mA Controlled Chemical Injection
The S420 is designed to follow an incoming 4-20mA signal from process control equipment such as:
- pH controllers
- ORP controllers
- Water treatment control systems
- Wastewater treatment monitors
- Industrial process control equipment
The pump's response to the 20mA signal can be scaled from 25% to 100% of maximum output, allowing operators to match pump performance to application requirements.
Manual or Automated Operation
The S420 offers two operating modes:
4-20mA Mode
- Output automatically adjusts based on the incoming signal
- User-selectable scaling from 25% to 100%
Manual Mode
- Adjustable output from 5% to 100%
- Simple potentiometer adjustment
Advanced Monitoring and Protection
To help support critical chemical feed applications, the S420 includes several built-in protection features:
- Leak detection with dedicated output relay
- Backup pump capability
- Remote standby input
- Run verification relay
- LED status indicators
- Drive fault indication
If configured with a backup pump, the primary unit can automatically transfer operation when a leak, power interruption, or drive fault occurs.
Key Features
- Accepts 4-20mA analog input signals
- Variable-speed operation
- Backup pump capability
- Leak detection with output relay
- LED operating status indicators
- NEMA 4X enclosed housing
- Brushless DC motor
- Indoor/outdoor rated construction
- Self-priming operation
- Can run dry
- Handles off-gassing solutions
- ±2% reproducibility
- 2-year warranty
Typical Applications
- Municipal water treatment
- Wastewater treatment
- Effluent treatment systems
- pH control systems
- ORP control systems
- Cooling towers
- Commercial pools
- Industrial process chemical feed
The Stenner S420 Series combines precise 4-20mA control, rugged construction, and dependable peristaltic pump technology to provide accurate chemical dosing for demanding process applications.

