Description
LMI Milton Roy P121-358SI Electromagnetic Dosing Pump 0.21 GPH 150 PSI 120V AC
The LMI Milton Roy P121-358SI is a compact electromagnetic diaphragm dosing pump designed for precise, low-flow chemical metering. It uses a solenoid-driven diaphragm mechanism to deliver accurate, repeatable doses of liquid chemicals at pressures up to 150 PSI. Front-panel dials allow independent adjustment of stroke length and stroke rate, giving operators direct control over the output flow. The pump carries NSF certification, indicating it meets standards for use in potable water treatment applications.
Specifications & What's Included
- Model: P121-358SI
- Drive mechanism: Electromagnetic (solenoid-driven diaphragm)
- Max flow rate: 0.21 GPH
- Max pressure: 150 PSI
- Input voltage: 120 V AC
- Current draw: 1.40 A
- Frequency: 50/60 Hz
- Certification: NSF Listed
- Front-panel controls: Stroke length dial, stroke speed/rate dial, STROKE indicator LED
- Pump head: Grey thermoplastic diaphragm head with four-bolt face plate
- Injection valve assembly with yellow priming knob and dual-check valve body
- Discharge tubing with white hex compression fitting
- Yellow polypropylene housing with integral base/foot mount
- UL listed (label visible on housing)
Applications
Electromagnetic dosing pumps like the LMI Milton Roy P121 series are standard equipment in municipal and industrial water treatment, used to feed chlorine, sodium hypochlorite, acid, caustic, or other treatment chemicals into a water stream at precisely controlled rates. The low maximum flow rate (0.21 GPH) makes this pump well suited to small-scale or residential water systems, well water chlorination, pH adjustment loops, and cooling tower chemical treatment. NSF listing makes it suitable for direct use in potable water systems where certification is required. LMI Milton Roy (a brand of Roper Technologies) has been a leading manufacturer of chemical metering pumps for water and wastewater applications for decades, and the P121 series is one of their widely deployed compact solenoid-driven models found in utilities, commercial buildings, and light industrial facilities.
This LMI Milton Roy P121-358SI Electromagnetic Dosing Pump is in used condition, pulled from a working environment where it was previously in service. The yellow housing is intact and shows normal wear consistent with field use. The pump head, injection valve assembly, and discharge tubing are all present as shown. The discharge fitting shows some mineral staining and discoloration around the bore — visible in the photos — which is typical for a pump used in chemical feed or water treatment service. The front-panel stroke and speed adjustment dials are present and intact. It has not been powered or tested at our facility. Please review all photos carefully and contact us with any questions before purchasing.
Warranty Information
Additional Information
Brand: |
LMI Milton Roy |
Model: |
P121-358SI |
MPN: |
P121-358SI |
Type: |
Electromagnetic Diaphragm Dosing Pump |
SKU: |
46214 |
Max Flow Rate: |
0.21 GPH |
Max Pressure: |
150 PSI |
Voltage: |
120 V AC |
Current: |
1.40 A |
Frequency: |
50/60 Hz |
Power Requirements: |
120V AC, 1.40A, 50/60 Hz |
Drive Mechanism: |
Electromagnetic |
Pump Head Material: |
Thermoplastic |
Certifications: |
NSF Listed |
Stroke Adjustment: |
Manual dial — stroke length and speed adjustable |
Seller Notes: |
Pump only — includes injection valve assembly and discharge tubing as shown. |
Country/Region of Manufacture: |
United States |
Application: |
Chemical metering, water treatment, chemical feed |
Condition Notes: |
This LMI Milton Roy P121-358SI Dosing Pump is in used condition, pulled from a working environment. Housing is intact with normal wear. Discharge fitting shows mineral staining typical of chemical service. Not tested at our facility. |
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 |
