SR0503N | 0.5HP (0.37kW) Sta-Rite 3-Phase Pump 💧 Professional Pool & Spa Circulation Solution

Engineered reliability meets exceptional efficiency for commercial and residential aquatic installations

📋 Product Overview

The SR0503N from Sta-Rite’s renowned 5P2R series represents the gold standard in compact three-phase pool circulation technology. This 0.5HP (0.37kW) professional-grade pump delivers robust performance with exceptional energy efficiency, making it the ideal choice for commercial pools, hot tubs, spas, and large residential installations where reliable, cost-effective water circulation is essential.

Manufactured by Pentair in their state-of-the-art Pisa, Italy facility, this pump combines precision Italian engineering with industry-leading materials and construction techniques. The three-phase motor design offers superior efficiency compared to single-phase alternatives, translating to lower operating costs and reduced environmental impact. With reinforced fiberglass construction, advanced self-priming technology, and a heavy-duty motor designed for continuous operation, the SR0503N delivers professional-grade performance that facility managers and pool operators can depend on year after year.

The pump’s compact footprint and versatile 1.5″ BSP connections make it suitable for a wide range of applications, from hotel pools and leisure center installations to large residential hot tubs and commercial spa facilities. Whether you’re upgrading aging equipment or specifying a new installation, the SR0503N offers the perfect balance of performance, reliability, and value.

⭐ Key Features

✅ Three-Phase Motor Efficiency – IE2-compliant motor delivers superior energy efficiency compared to single-phase alternatives, reducing operating costs by 15-25% while providing smoother, quieter operation ideal for commercial environments

✅ Reinforced Fiberglass Construction – Advanced composite body offers exceptional temperature and corrosion resistance, extending service life in challenging pool and spa environments while maintaining structural integrity under high-pressure operations

✅ Self-Priming Diffuser Design – Innovative engineering eliminates manual priming hassles, automatically drawing water from up to 2.5 meters below pump level for versatile installation options and faster startup times

✅ High Head Impeller Performance – Precision-molded glass-filled polycarbonate impeller with smooth water passages delivers outstanding hydraulic efficiency, making it ideal for installations where the equipment room is located far from the pool

✅ Stainless Steel Components – Critical components including the shaft and pump clamp feature corrosion-resistant stainless steel construction (AISI 304), ensuring reliable operation even in harsh chemical environments

✅ Advanced Mechanical Seal System – Precision-lapped carbon ceramic and stainless steel mechanical seal provides maximum drip-proof protection and corrosion-free performance, significantly reducing maintenance requirements and extending operational lifespan

✅ Heavy-Duty Motor Design – 50Hz motor features permanently lubricated SKF sealed bearings and thermal protection, engineered for continuous, quiet operation with superior cooling even in high ambient temperature environments

✅ Hi-Rise Mounting Base – Unique elevated mounting design enhances stability during operation and simplifies installation procedures, reducing setup time and ensuring proper alignment for optimal performance

✅ Transparent Inspection Lid – See-through trap lid allows visual monitoring of strainer basket without opening the housing, while withstanding 4 bar test pressure and high vacuum conditions for complete safety

✅ Extra-Large 5″ Strainer Basket – Generous basket capacity with secure lock-in design reduces cleaning frequency and maintenance intervals, keeping your system running efficiently with minimal intervention

🔧 Technical Specifications

Specification	Detail
Model Number	SR0503N (P-STR-053)
Power Output	0.5HP (0.37kW)
Voltage	380-420V
Phase	3-Phase
Frequency	50Hz
Motor Efficiency	IE2 Compliant
Protection Rating	IP-X5
Suction Connection	1.5″ BSP
Delivery Connection	1.5″ BSP
Union Diameter	50mm Internal
Unions Included	Yes
Maximum Flow @ 8m Head	8 m³/h
Maximum Suction Lift	2.5 meters
Priming Type	Self-priming
Body Material	Reinforced Fiberglass
Impeller Material	Glass-filled Polycarbonate
Shaft Material	Stainless Steel (AISI 304)
Seal Type	Carbon Ceramic + Stainless Steel Mechanical Seal
Strainer Basket Size	5″ (XL capacity)
Strainer Lid Type	Transparent, 4 bar pressure rated
Mounting Base	Hi-Rise design
Bearings	SKF Sealed, Permanently Lubricated
Thermal Protection	Integrated (Three-phase)
Dimensions (W × L)	288mm × 514mm
Weight	13.9kg
Salt Resistance	0.40% (4 g/l)
Suitable For	Pools 30-80 m³
Manufacture Origin	Made in Italy (Pentair Pisa facility)

💰 Usage Costs & Running Expenses

📊 Annual Running Cost Calculation

Seasonal Pool Operation (6 Months):

• Power consumption: 0.37 kW
• Daily operation: 8 hours/day
• Seasonal usage: 8 hours × 180 days = 1,440 hours/year
• UK commercial electricity rate: £0.26 per kWh (November 2024 average)
• ✅ Annual cost: 0.37 kW × 1,440 hours × £0.26 = £138.53

Year-Round Commercial Operation (12 Months):

• Daily operation: 10 hours/day
• Annual usage: 10 hours × 365 days = 3,650 hours/year
• UK commercial electricity rate: £0.26 per kWh
• ✅ Annual cost: 0.37 kW × 3,650 hours × £0.26 = £351.05

Extended Commercial Operation (Heated Pool/Spa):

• Daily operation: 16 hours/day
• Annual usage: 16 hours × 365 days = 5,840 hours/year
• UK commercial electricity rate: £0.26 per kWh
• ✅ Annual cost: 0.37 kW × 5,840 hours × £0.26 = £561.68

⚡ Three-Phase Efficiency Advantage

Compared to equivalent single-phase 0.5HP pump (0.41 kW):

❌ Single-phase annual cost (seasonal): 0.41 kW × 1,440 hours × £0.26 = £153.50 ✅ Three-phase annual cost (seasonal): 0.37 kW × 1,440 hours × £0.26 = £138.53 💷 Annual saving: £14.97 (9.7% reduction)

❌ Single-phase annual cost (year-round, 10h/day): 0.41 kW × 3,650 hours × £0.26 = £389.09 ✅ Three-phase annual cost (year-round, 10h/day): 0.37 kW × 3,650 hours × £0.26 = £351.05 💷 Annual saving: £38.04 (9.8% reduction)

❌ Single-phase annual cost (extended operation): 0.41 kW × 5,840 hours × £0.26 = £622.66 ✅ Three-phase annual cost (extended operation): 0.37 kW × 5,840 hours × £0.26 = £561.68 💷 Annual saving: £60.98 (9.8% reduction)

Note: Three-phase motors offer additional benefits including smoother operation, reduced vibration, lower maintenance costs, and extended service life compared to single-phase alternatives.

🎯 Real World Examples & Applications

🏊‍♂️ Municipal & Leisure Center Pools – Perfect for community swimming pools requiring reliable, energy-efficient circulation with minimal maintenance. The robust three-phase motor handles extended daily operation schedules, while the reinforced fiberglass construction withstands heavy chemical treatment regimes. Typical installation includes 8-12 hour daily operation with professional maintenance schedules.

🏢 Hotel & Resort Pool Systems – Ideal for hospitality environments where guest experience depends on crystal-clear water and quiet operation. The self-priming design simplifies equipment room layout, while the transparent strainer lid enables quick visual inspections without interrupting service. Commonly specified for heated outdoor pools and rooftop installations requiring reliable performance.

🛁 Commercial Spa & Hot Tub Facilities – Excellent choice for health clubs, wellness centers, and spa facilities operating multiple hot tubs. The high head impeller maintains strong circulation even with complex plumbing layouts and elevated spa positions. Salt-resistant construction (up to 4 g/l) accommodates various water treatment systems while the compact footprint fits constrained equipment spaces.

🌊 Large Residential Pool Installations – Outstanding solution for substantial domestic pools (30-80 m³) where homeowners demand professional-grade reliability with economical operating costs. The three-phase efficiency reduces electricity consumption compared to residential single-phase alternatives, providing significant long-term savings for properties with three-phase electrical supply.

🔄 Equipment Upgrades & Replacements – Exceptional replacement option for aging single-phase pumps in facilities upgrading to more efficient equipment. The standardized 1.5″ BSP connections ensure compatibility with existing plumbing, while the performance specifications match or exceed legacy equipment. Typical payback period of 2-4 years through energy savings alone.

☀️ Seasonal Operations – Well-suited for outdoor pool facilities operating 6-7 months annually, including outdoor lidos, campsite pools, and seasonal resort installations. The self-priming capability and corrosion-resistant construction handle seasonal startup and winterization procedures reliably year after year.

💡 Cost Savings Examples

📍 Scenario 1: Upgrading from Older Single-Phase 0.5HP Pump

Old pump consumption: 0.50 kW (typical older single-phase technology) New SR0503N consumption: 0.37 kW (modern three-phase IE2 motor)

For year-round commercial operation (10 hours/day):

• ❌ Old pump annual cost: 0.50 kW × 3,650 hours × £0.26 = £474.50
• ✅ SR0503N annual cost: 0.37 kW × 3,650 hours × £0.26 = £351.05
• 💰 Annual saving: £123.45
• 📈 3-year saving: £370.35
• ⏱️ Simple payback period: Approximately 2-3 years (depending on pump purchase price)

📍 Scenario 2: Municipal Pool Operating Extended Hours

Municipal pool operation: 12 hours/day, 7 days/week, 52 weeks/year Annual usage: 12 hours × 365 days = 4,380 hours/year

Upgrading from 0.55kW older equipment:

• ❌ Old pump annual cost: 0.55 kW × 4,380 hours × £0.26 = £626.34
• ✅ SR0503N annual cost: 0.37 kW × 4,380 hours × £0.26 = £421.45
• 💷 Annual saving: £204.89
• 📊 5-year saving: £1,024.45
• 💵 10-year saving: £2,048.90

Additional benefits: Reduced maintenance costs due to superior mechanical seal design, extended service life from premium SKF bearings, and improved reliability minimizing downtime and emergency repairs.

📍 Scenario 3: Hotel with Multiple Pool/Spa Systems

Facility: Boutique hotel with outdoor pool and two hot tubs Total pump requirement: 3 × SR0503N pumps Average operation: 10 hours/day year-round

Compared to using three single-phase 0.41kW pumps:

• ❌ Single-phase total annual cost: 3 pumps × £389.09 = £1,167.27
• ✅ SR0503N three-phase total annual cost: 3 pumps × £351.05 = £1,053.15
• 💸 Annual saving across facility: £114.12
• 📈 5-year operational saving: £570.60

Additional value considerations:

• Reduced noise levels enhance guest experience
• Lower vibration extends plumbing system lifespan
• Simplified maintenance procedures reduce labor costs
• Professional-grade reliability minimizes guest complaints

📥 Downloads & Resources

📄 Sta-Rite Single Speed Pumps Installation Manual – Comprehensive installation, operation, and maintenance guide for the 5P2R series including electrical connection diagrams, troubleshooting procedures, and safety instructions (PDF)

📄 Sta-Rite 5P2R Product Datasheet – Technical specifications, performance curves, dimensional drawings, and model selection guide for the complete La Sta-Rite range (PDF)

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🌟 Why Buy From Parts4tubs?

✅ Genuine Pentair/Sta-Rite Equipment – We supply only authentic products direct from authorized distribution channels, ensuring full manufacturer warranty coverage and genuine replacement parts availability

✅ Expert Technical Support – Our team understands commercial pool and spa applications, providing professional guidance on pump selection, installation requirements, and system optimization

✅ Competitive Pricing – Direct supplier relationships and efficient operations enable us to offer excellent value on professional-grade equipment without compromising on quality or service

✅ Fast UK Delivery – Comprehensive stock holdings and reliable logistics partners ensure prompt delivery to your installation site, minimizing project delays and downtime

✅ Trade & Contractor Accounts – Dedicated account management, preferential pricing, and flexible payment terms available for pool professionals, maintenance contractors, and facility management companies

✅ Complete System Solutions – Beyond pumps, we supply filters, heaters, controllers, and all ancillary components needed for complete pool and spa installations from trusted manufacturers

🏆 Why Choose the SR0503N Sta-Rite Pump?

✅ Superior Energy Efficiency – Three-phase IE2-compliant motor technology delivers measurable operating cost reductions compared to single-phase alternatives, with typical annual savings of £40-200 depending on usage patterns and facility requirements

✅ Professional-Grade Construction – Manufactured by Pentair in Italy using premium materials and precision engineering, this pump meets the demanding standards of commercial pool professionals and discriminating residential customers worldwide

✅ Proven Long-Term Reliability – The 5P2R series represents decades of refinement and real-world performance, with installations operating reliably for 10-15+ years when properly maintained, minimizing total cost of ownership

✅ Simplified Maintenance Access – Thoughtful design features including the stainless steel quick-release clamp, transparent inspection lid, and accessible serviceable components reduce routine maintenance time and complexity

✅ Versatile Installation Flexibility – Self-priming capability up to 2.5m, compact footprint, and standardized connections accommodate diverse installation scenarios from basement equipment rooms to rooftop plant areas

✅ Comprehensive Safety Features – Integrated thermal protection, IP-X5 rating, pressure-rated components, and robust mechanical seal design ensure safe, trouble-free operation in accordance with UK and EU safety regulations

✅ Future-Proof Investment – The stainless steel locking clamp design allows potential future upgrades to variable speed technology using the same pump housing, protecting your equipment investment as technology advances

✨ Summary

The SR0503N Sta-Rite 0.5HP three-phase pump delivers an exceptional combination of energy efficiency, robust construction, and proven reliability that makes it the intelligent choice for commercial pools, spas, and large residential installations. With advanced features including self-priming operation, high head impeller performance, and premium stainless steel components, this Italian-engineered pump provides professional-grade performance with significantly lower operating costs compared to single-phase alternatives. Whether you’re specifying new construction, upgrading aging equipment, or seeking to reduce operational expenses, the SR0503N offers outstanding value backed by Pentair’s reputation for quality and the comprehensive support of Parts4tubs.