STENNER 45MP5 PUMP FX 25PSI 50GPD 120V/60HZ 3/8W

The Stenner 45MP5 (45MHP5 / 45M5 Fixed Rate Series) peristaltic chemical metering pump is a commercial-grade, self-priming positive displacement feed pump engineered for commercial aquatic automation, water treatment, and agricultural chemical feed. Operating at a fixed output rate of 50 GPD (Gallons Per Day) against up to 25 PSI, it is the industry standard feed mechanism paired with Pool Link 500/1000 Series controllers for direct injection of liquid sodium hypochlorite (12.5% bleach) and 31.45% muriatic acid into pressurized pool recirculation lines.

Nomenclature & Model Decoding

• 45: Stenner 45 Series single-head peristaltic pump platform.

• M / MP: Mechanical gear-driven motor platform.

• 5: #5 Santoprene Pump Tube (high-output tubing insert).

• FX: Fixed output rate (100% duty cycle when powered; dosing modulated externally via controller duty-cycling).

• 25PSI: Low-pressure rating (up to 25 PSI / 1.72 bar), optimized for high-volume commercial pool returns.

• 50GPD: 50.0 US Gallons Per Day nominal delivery capacity (~2.08 GPH / ~7.88 LPH).

• 120V/60HZ: Standard North American 120V AC, 60 Hz electrical service.

• 3/8W: 3/8" Outer Diameter (OD) white opaque suction/discharge tubing and compression fittings.

Mechanical Architecture & Operational Dynamics

• Peristaltic Positive Displacement: Three-roller planetary gear assembly continuously compresses and releases a flexible Santoprene tube inside the pump head. Fluid is trapped between the advancing rollers, producing positive displacement that cannot lose prime or air-lock.

• Off-Gas & Vapor Handling: Unlike electronic diaphragm metering pumps that air-bind when pumping decomposing liquid chlorine ($O_2$ off-gas) or fuming muriatic acid ($HCl$), peristaltic compression easily pushes gas pockets through the line without vapor lock.

• Self-Priming & Anti-Siphon Protection: Self-priming against a 25-foot vertical suction lift. The pinch rollers maintain a mechanical seal against the tube at all times, preventing chemical siphoning into the pool loop without requiring separate spring-loaded anti-siphon valves.

• Chemical Isolation: Fluid contacts only the inside of the Santoprene pump tube, polyethylene delivery tubing, and duckbill check valve, keeping corrosive chemicals completely isolated from the motor and mechanical drive gears.

Technical Specifications

• Flow Capacity: 50.0 GPD (approx. 2.08 GPH / 78.9 mL/min / 189.3 L/day) at 25 PSI.

• Maximum Working Pressure: 25 PSI (approx. 1.72 bar).

• Electrical Service: 120V AC, 60 Hz, 1-Phase, 1.7 A (approx. 1/30 HP shaded-pole gear motor with thermal overload protection).

• Duty Cycle: Continuous duty rated; controlled via Pool Link feed relays via proportional pulse or timed duty cycles.

• Tube Material: FDA-approved Santoprene (cross-linked EPDM/polypropylene elastomer) #5 size tube with 1/4" or 3/8" quick-release ferrules.

• Turndown Ratio: Fixed output (100% flow when powered); controller interlocks modulate chemical delivery.

• Suction / Discharge Connections: 3/8" OD UV-resistant white polyethylene tubing with compression nuts and ferrule sleeves.

• Ambient Operating Limits: 104°F (40°C) max ambient temperature; process liquid temperature up to 104°F (40°C).

Routine Maintenance & Consumables

• • • Santoprene Tube Life: Typically 500 to 1,000 running hours (or seasonal replacement every 4–6 months in heavy commercial pools).

    • Roller Assembly Lubrication: Clean and apply Stenner silicone lubricant to the roller assembly and inner pump housing during every tube swap to minimize friction and prevent tube scrubbing.

    • Duckbill Check Valve Inspection: Inspect the duckbill check valve at the pipe injection fitting annually for chemical hardening, calcification, or swelling.