Description
LMI Milton Roy AA971-358SI Electromagnetic Dosing Pump 120V 0.42 GPH 140 PSI NSF
The LMI Milton Roy AA971-358SI is a microprocessor-controlled electromagnetic diaphragm dosing pump designed for precise chemical metering in water treatment and industrial process applications. It uses an electromagnetically driven diaphragm to deliver repeatable, accurate dosing at pressures up to 140 PSI, with the flow rate adjustable via a front-panel stroke-length dial. The microprocessor control board supports multiple operating modes — internal timer, external contact (Digi-Pulse), and manual priming — making it adaptable to a wide range of dosing control scenarios.
Specifications & What's Included
- Model: AA971-358SI
- Pump type: Electromagnetic diaphragm metering / dosing pump
- Max flow rate: 0.42 GPH
- Max discharge pressure: 140 PSI
- Power: 120V AC, 50/60 Hz, 1.40 A
- Control: Microprocessor with LCD display (shows stroke rate in strokes/min)
- Operating modes: INT (internal timer), EXT (external/Digi-Pulse), Timer
- Stroke adjustment: 0–100% via front-panel dial
- Input connectors: Digi-Pulse input (4-pin circular) and Level Switch input (7-pin circular), on lower front panel
- Pump head: Black diaphragm-type liquid end with check valve manifold and priming vent
- Certifications: UL, CE, NSF listed
- Manufacturer: LMI Milton Roy, Acton, MA USA
- Includes: Pump unit with attached power cord (NEMA 5-15P plug)
- Not included: Inlet/outlet tubing, chemical lines, mounting hardware
Applications
Electromagnetic diaphragm metering pumps like the LMI Milton Roy AA971 series are standard equipment in water treatment, municipal water supply, and industrial process systems where precise, repeatable chemical addition is required. Common applications include chlorine and hypochlorite disinfection, pH adjustment (acid/caustic feed), scale inhibitor and corrosion control chemical dosing, and coagulant/flocculent addition in drinking water and wastewater systems. The NSF listing makes the AA971-358SI well suited for potable water treatment installations where certification is required. The Digi-Pulse input allows the pump to be paced by a flow meter pulse signal for flow-proportional dosing, while the Level Switch input supports dry-run protection. LMI Milton Roy has been a major manufacturer of chemical metering pumps since the 1960s, and the AA series electromagnetic pumps have been widely deployed in municipal, commercial, and light industrial water treatment systems across North America.
This LMI Milton Roy AA971-358SI Electromagnetic Dosing Pump is in used condition, pulled from a working environment where it was previously in service. It has been visually inspected and photographed. The housing and control panel are in good cosmetic shape overall. The liquid end valve assembly and inlet fitting show chemical residue and deposits typical of a pump that has been actively dosing chemicals — this is normal for this type of equipment. The power cord plug shows light surface oxidation on the prongs, consistent with normal use. Please review all photos carefully to assess cosmetic condition before purchasing. Please view our photo set and contact us if you have any questions.
Warranty Information
Additional Information
Brand: |
LMI Milton Roy |
Model: |
AA971-358SI |
MPN: |
AA971-358SI |
Type: |
Electromagnetic Metering / Dosing Pump |
SKU: |
42859 |
Seller Notes: |
Pump only with power cord — no inlet/outlet tubing or chemical lines included. |
Country/Region of Manufacture: |
United States |
Form Factor: |
Freestanding / Base-Mounted |
Power Requirements: |
120V AC, 50/60 Hz, 1.40 A |
Voltage: |
120V AC |
Current Rating: |
1.40 A |
Frequency: |
50/60 Hz |
Max Flow Rate: |
0.42 GPH |
Max Pressure: |
140 PSI |
Pump Mechanism: |
Electromagnetic Diaphragm |
Control Type: |
Microprocessor |
Stroke Adjustment: |
0–100% via front-panel dial |
Display: |
LCD — shows stroke rate in strokes/min |
Input Connectors: |
Digi-Pulse (4-pin) and Level Switch (7-pin) |
Certifications: |
UL, CE, NSF |
Application: |
Chemical dosing, water treatment, disinfection |
Compatible With: |
Standard liquid chemical feed systems, water treatment |
Manufacturer Location: |
Acton, MA 01720, USA |
Condition Notes: |
This LMI Milton Roy AA971-358SI Electromagnetic Dosing Pump is in used condition, pulled from a working environment. The housing and controls are in good cosmetic shape. The liquid end shows chemical residue typical of active service use. |
California Prop 65 Warning: |
WARNING: This product can expose you to chemicals including lead and lead compounds, and DEHP (a phthalate), which are known to the State of California to cause cancer and birth defects or other reproductive harm. Go to P65Warnings.ca.gov |
