💧 Certikin Hydrostar MK4 5.7hp (4.3kW) 3-Phase Commercial Pool Pump (WHSR503/4)

Superior Power Meets Whisper-Quiet Efficiency for Demanding Aquatic Facilities

📋 Product Overview

The Certikin Hydrostar MK4 5.7hp (4.3kW) three-phase commercial pool pump represents the cutting edge of commercial aquatic circulation technology. This powerhouse pump combines exceptional flow performance with remarkably quiet operation, making it the ideal choice for large-scale commercial installations where both power and environmental comfort matter.

Engineered specifically for demanding commercial environments, the WHSR503/4 model delivers outstanding hydraulic efficiency through its completely redesigned shape and optimised flow path. The pump’s robust three-phase motor provides reliable, energy-efficient operation while the UV-stabilised glass-filled polypropylene construction ensures years of dependable service in even the harshest chemical environments.

Perfect for water parks, Olympic-sized pools, large hotel complexes, leisure centres, and high-end resort facilities, this pump delivers the performance commercial operators demand with the efficiency modern facilities require. The innovative Hydrostar MK4 series sets new standards for what commercial pool equipment can achieve in terms of flow rate, energy efficiency, and operational quietness.

⭐ Key Features

✅ Powerful 5.7hp (4.3kW) Three-Phase Motor – Delivers exceptional flow rates for large commercial pools, water features, and demanding circulation systems whilst maintaining superior energy efficiency compared to single-phase alternatives

✅ Redesigned Hydraulic System – Completely re-engineered shape and flow path maximises hydraulic efficiency, delivering significantly improved flow rates whilst reducing energy consumption per litre pumped

✅ Exceptionally Quiet Operation – Advanced acoustic design and precision engineering result in whisper-quiet running even at high flow rates, ideal for noise-sensitive environments like hotel pools and indoor leisure facilities

✅ UV Stabilised Glass-Filled Polypropylene Housing – Industrial-grade construction provides exceptional resistance to chemical corrosion, UV degradation, and mechanical stress for extended service life in demanding commercial applications

✅ Clear Polycarbonate Strainer Lid – Allows instant visual inspection of basket contents without opening the pump, reducing maintenance time and enabling quick debris checks during operation

✅ Large 6-Litre Strainer Basket – Oversized debris collection capacity reduces cleaning frequency and helps maintain optimal flow rates between service intervals in high-use facilities

✅ Tool-Free Lid Access System – Ergonomic quarter-turn lid lock ring with integrated handles enables quick basket access without tools, minimising maintenance downtime and simplifying routine service

✅ Enclosed Glass-Filled Noryl Impeller – Advanced composite material delivers superior wear resistance and maintains efficiency over extended operating periods whilst resisting chemical attack and cavitation damage

✅ 431 Stainless Steel Motor Shaft – Premium corrosion-resistant construction ensures reliable operation in chemically aggressive pool environments and extends pump lifespan significantly

✅ IP55 Motor Protection Rating – Comprehensive weather and dust protection allows flexible installation locations including covered outdoor pump rooms and exposed equipment areas

🔧 Technical Specifications

Specification	Detail
Model Number	WHSR503/4
Power Output	5.7hp (4.3kW)
Motor Type	Three-phase
Phase Connection	WYE/STAR (Export) / DELTA (AUS/NZ)
Motor Protection	IP55
Pump Housing Material	UV stabilised glass-filled polypropylene
Strainer Lid	Clear polycarbonate
Strainer Basket Capacity	6 litres
Impeller Type	Enclosed glass-filled Noryl
Motor Shaft	431 stainless steel
Inlet Connection	90mm metric half union
Outlet Connection	90mm metric half union
Minimum Pipe Size	80mm inlet and outlet
Maximum Operating Temperature	40°C (104°F)
Minimum Operating Temperature	4°C (39.2°F)
Maximum Test Pressure	35 PSI (2.4 bar)
Warranty Coverage	1 year comprehensive commercial warranty

💰 Usage Costs & Running Expenses

📊 Annual Running Cost Calculation

Understanding the operational costs of commercial pool equipment is crucial for facility budgeting and long-term financial planning. Here’s a detailed breakdown of annual running costs for the Hydrostar MK4 5.7hp pump:

Power Consumption: 4.3 kW
Typical Commercial Pool Usage: 10 hours/day × 365 days = 3,650 hours/year
UK Commercial Electricity Rate: £0.27 per kWh (average commercial rate, November 2025)

✅ Annual Energy Cost:
4.3 kW × 3,650 hours × £0.27 = £4,236.45 per year

🏊 Commercial Usage Scenarios

Scenario 1: 🏢 Busy Hotel Pool (Year-Round Operation)

Usage Pattern: 12 hours/day, 365 days/year = 4,380 hours
Annual Cost: 4.3 kW × 4,380 hours × £0.27 = £5,083.74/year
Monthly Cost: Approximately £423.65/month

Scenario 2: 🏊‍♂️ Public Leisure Centre (Extended Hours)

Usage Pattern: 14 hours/day, 365 days/year = 5,110 hours
Annual Cost: 4.3 kW × 5,110 hours × £0.27 = £5,929.11/year
Monthly Cost: Approximately £494.09/month

Scenario 3: ☀️ Outdoor Seasonal Pool (Summer Operation)

Usage Pattern: 10 hours/day, 180 days/year = 1,800 hours
Annual Cost: 4.3 kW × 1,800 hours × £0.27 = £2,088.90/year
Seasonal Operating Cost: £348.15/month (during 6-month season)

Scenario 4: 🌊 Water Park Feature (Continuous Operation)

Usage Pattern: 16 hours/day, 365 days/year = 5,840 hours
Annual Cost: 4.3 kW × 5,840 hours × £0.27 = £6,775.68/year
Monthly Cost: Approximately £564.64/month

⚡ Energy Efficiency Advantages

Three-Phase Motor Benefits:

• ✅ Approximately 15-20% more energy efficient than equivalent single-phase motors
• ✅ Lower operating temperatures extend motor life and reduce cooling requirements
• ✅ More stable power delivery results in smoother operation and reduced mechanical stress
• ✅ Better suited to commercial continuous-duty applications with extended run times

💡 Cost Savings & Upgrade Benefits

📍 Scenario 1: Upgrading from Older Hydrostar MK3 Technology

❌ Old Technology (Typical 5.5kW older-generation pump):

• Power consumption: 5.5 kW
• Annual usage: 3,650 hours
• Energy rate: £0.27/kWh
• Annual cost: £5,420.25

✅ New Hydrostar MK4 (4.3kW):

• Power consumption: 4.3 kW
• Annual usage: 3,650 hours
• Energy rate: £0.27/kWh
• Annual cost: £4,236.45

💷 Annual Saving: £1,183.80
💰 Three-Year Saving: £3,551.40
⏱️ Payback Period: Typically 18-24 months depending on installation costs

The improved hydraulic design means the Hydrostar MK4 delivers comparable or superior flow rates whilst consuming significantly less power than older-generation models.

📍 Scenario 2: Replacing Oversized Inefficient Pump

Many older commercial installations feature oversized pumps that were specified with excessive safety margins, resulting in wasted energy and unnecessary operating costs.

❌ Typical Oversized 7.5hp (5.5kW) Installation:

• Power consumption: 5.5 kW
• Annual usage: 4,380 hours (12 hours/day)
• Energy rate: £0.27/kWh
• Annual cost: £6,503.40

✅ Right-Sized Hydrostar MK4 5.7hp (4.3kW):

• Power consumption: 4.3 kW
• Annual usage: 4,380 hours
• Energy rate: £0.27/kWh
• Annual cost: £5,083.74

💷 Annual Saving: £1,419.66
💰 Five-Year Saving: £7,098.30
📈 ROI: 15-25% annual return on investment through energy savings alone

📍 Scenario 3: Converting from Single-Phase to Three-Phase

❌ Single-Phase 5hp Equivalent (~4.5kW effective consumption):

• Power consumption: 4.5 kW
• Annual usage: 3,650 hours
• Energy rate: £0.27/kWh
• Annual cost: £4,428.75

✅ Three-Phase Hydrostar MK4 (4.3kW):

• Power consumption: 4.3 kW
• Annual usage: 3,650 hours
• Energy rate: £0.27/kWh
• Annual cost: £4,236.45

💷 Annual Saving: £192.30
Additional Benefits:

• ⚡ More reliable operation with reduced thermal stress
• ⚡ Lower maintenance requirements due to cooler running
• ⚡ Better suited to commercial continuous-duty cycles
• ⚡ Improved power factor reduces demand charges in some facilities

📊 Long-Term Cost Protection

Energy Price Volatility Protection: Commercial electricity prices have shown significant volatility, rising from approximately 14-15p/kWh in early 2021 to current levels around 26-28p/kWh. Every kW of power consumption matters more than ever.

If energy prices rise to £0.30/kWh (conservative projection):

• ❌ 5.5kW older pump annual cost: £6,022.50
• ✅ 4.3kW Hydrostar MK4 annual cost: £4,708.50
• 💰 Annual saving increases to £1,314.00

Investing in energy-efficient equipment now provides protection against future energy price increases and helps control long-term operating expenses.

🎯 Real World Examples & Applications

🏊 Municipal Swimming Pools

The Hydrostar MK4 5.7hp pump excels in municipal pool applications where reliability, efficiency, and quiet operation are paramount. Typical installations include 25-metre and 33-metre competition pools, leisure pools with splash features, and teaching pools requiring consistent circulation.

Performance Benefits:

• Handles flow rates of 60-90 m³/hr depending on system head
• Quiet operation minimises noise in indoor aquatic facilities
• Robust construction withstands intensive daily use
• Three-phase reliability ensures consistent performance during extended operating hours

Typical Application: 25-metre, 6-lane municipal competition pool with 450,000-litre capacity requiring 4-6 hour turnover rate

🏨 Hotel & Resort Pools

Premium hospitality facilities demand equipment that operates quietly while providing exceptional water quality. The Hydrostar MK4 delivers whisper-quiet performance that won’t disturb guests whilst ensuring crystal-clear pool water through efficient circulation and filtration.

Performance Benefits:

• Ultra-quiet operation maintains peaceful pool environment
• Reliable 24/7 operation capability for year-round facilities
• Clear strainer lid enables quick visual inspections during busy periods
• Corrosion-resistant construction handles chlorine, salt systems, and aggressive water chemistry

Typical Application: Hotel rooftop pool or indoor leisure pool with spa features, operating 12-16 hours daily with overnight circulation cycles

🌊 Water Parks & Leisure Centres

High-traffic aquatic facilities require pumps that can handle demanding duty cycles while maintaining energy efficiency. The Hydrostar MK4’s robust construction and efficient motor design make it ideal for water park features, wave pools, and leisure pool circulation systems.

Performance Benefits:

• Handles continuous operation during peak summer months
• Large 6-litre strainer basket reduces maintenance frequency during busy periods
• Energy-efficient operation helps control costs during extended operating seasons
• IP55 protection allows flexible installation in covered outdoor pump rooms

Typical Application: Water park lazy river or interactive play feature requiring high flow rates with year-round or seasonal operation

🏢 Commercial & Industrial Water Features

Large decorative water features in commercial developments, shopping centres, and corporate facilities require reliable circulation without excessive noise. The Hydrostar MK4 provides the power needed for fountains and cascades whilst operating quietly in public spaces.

Performance Benefits:

• Sufficient power for impressive water displays and features
• Quiet operation appropriate for public and corporate environments
• Reliable three-phase operation reduces maintenance call-outs
• Chemical-resistant construction handles fountain water treatment systems

Typical Application: Large commercial fountain or reflecting pool in shopping centre, corporate campus, or public plaza

🔄 Upgrade & Retrofit Projects

Facility managers replacing aging equipment will find the Hydrostar MK4 offers straightforward installation with significant performance improvements. Standard 90mm connections and compact footprint typically allow direct replacement of older pumps without extensive pipework modifications.

Performance Benefits:

• Modern efficiency standards reduce ongoing operating costs
• Improved hydraulics may allow downsizing from older oversized installations
• Tool-free maintenance reduces ongoing servicing time and costs
• One-year commercial warranty provides peace of mind for capital investment

Typical Application: Replacing 15-20 year old commercial pump installations with modern energy-efficient technology while maintaining or improving flow performance

📥 Downloads & Resources

📄 Installation and Operation Manual – Comprehensive guide covering installation, startup procedures, maintenance schedules, winterisation, troubleshooting, and warranty information (Commercial Pump Manual W99245, PDF)
Download Installation Manual

📄 Hydrostar MK4 Technical Leaflet – Product specifications, performance curves, dimensional drawings, and technical data (PDF)
Download Technical Leaflet

🏆 Why Choose the Certikin Hydrostar MK4 5.7hp Pump

✅ Proven Commercial Reliability – Certikin’s established reputation in commercial pool equipment means you’re investing in proven technology backed by comprehensive technical support and genuine OEM parts availability

✅ Energy Efficiency That Protects Your Budget – Lower power consumption compared to older technology means reduced operating costs year after year, with improved efficiency helping offset rising energy prices

✅ Whisper-Quiet Operation – Advanced acoustic design ensures minimal noise impact in noise-sensitive environments like hotels, indoor pools, and leisure facilities where guest comfort matters

✅ Reduced Maintenance Requirements – Tool-free access, large strainer basket, clear inspection lid, and robust construction all combine to minimise maintenance time and reduce ongoing servicing costs

✅ Commercial-Grade Construction – UV-stabilised housing, stainless steel shaft, and chemical-resistant materials ensure years of reliable operation in demanding commercial pool environments

✅ Future-Proof Investment – Modern energy-efficient design provides protection against rising electricity costs whilst meeting current commercial equipment standards and expectations

✅ Comprehensive Technical Support – Backed by Waterco’s global commercial pool expertise with local technical support, warranty coverage, and genuine replacement parts availability

✅ Three-Phase Commercial Power – Superior efficiency, reliability, and suitability for continuous commercial duty cycles compared to single-phase alternatives

🛒 Why Buy From Parts4tubs?

✅ Genuine Commercial Equipment – All pumps supplied are authentic Certikin products with full manufacturer warranties, not grey-market or parallel imports that void coverage

✅ Commercial Pool Expertise – Specialist knowledge of commercial aquatic installations means you get the right advice for your specific application requirements

✅ Competitive Commercial Pricing – Direct sourcing and volume relationships with manufacturers ensure competitive pricing on genuine commercial equipment

✅ Technical Support Available – Access to knowledgeable staff who understand commercial pool systems and can provide application guidance and technical assistance

✅ Fast Dispatch & Delivery – Quick order processing and reliable delivery ensures minimal downtime when replacing critical commercial equipment

✅ Complete Product Range – One-stop sourcing for pumps, filters, chemical dosing systems, and all commercial pool equipment needs from trusted manufacturers

✅ Trade Account Facilities – Flexible payment terms and account facilities available for commercial contractors, facility managers, and regular trade customers

✨ Summary

The Certikin Hydrostar MK4 5.7hp (4.3kW) three-phase commercial pool pump (WHSR503/4) represents the optimal balance of power, efficiency, and reliability for demanding commercial aquatic applications. With its redesigned hydraulic system delivering improved flow rates, exceptionally quiet operation suitable for noise-sensitive environments, and robust construction engineered for years of commercial service, this pump sets new standards for commercial pool circulation equipment.

The energy-efficient 4.3kW three-phase motor helps control operating costs whilst the large 6-litre strainer basket and tool-free maintenance features reduce ongoing servicing requirements. Whether you’re managing a municipal pool, hotel facility, leisure centre, or water park, the Hydrostar MK4 delivers the performance and reliability commercial operators demand with the efficiency modern facilities require.

Invest in proven commercial technology that will deliver years of dependable service whilst helping control energy costs and maintenance expenses. The Certikin Hydrostar MK4 5.7hp pump – where commercial-grade power meets operational efficiency.