🌀 Kripsol Ondina-OK 51T1 0.50HP Three Phase Pool Pump

🔇 Compact, Silent & Salt Water Compatible – High Efficiency IE2 Motor, Made in EU with 3-Year Warranty

📋 Product Overview

The Kripsol Ondina-OK 51T1 is a high-efficiency swimming pool circulation pump specifically optimised for small to medium residential pools up to 75m³. Part of the Classic Line from Kripsol (now part of Hayward), this compact three-phase pump delivers reliable performance with remarkably quiet operation – making it ideal for installations where noise is a concern, including underground technical equipment boxes and small plant rooms.

Featuring an energy-efficient IE2 rated motor and AISI 316 stainless steel mechanical seal, the OK 51T1 handles both fresh water and salt water/sea water environments with ease. The 0.50HP (368W P2) motor delivers 8.5m³/h flow rate at 8 metres head, providing excellent circulation for residential pools.

Built in the EU with quality materials including glass fibre reinforced polypropylene housing and Noryl® impeller, this pump combines durability with efficiency. The quick-seal lid with wing nuts ensures easy access to the 1.75 litre prefilter basket for routine maintenance. Backed by a comprehensive 3-year manufacturer warranty, the Ondina-OK represents outstanding value for residential pool installations.

⭐ Key Features

✅ High Efficiency IE2 Motor – Energy-efficient motor exceeds standard efficiency requirements, reducing running costs and environmental impact

✅ Whisper-Quiet Operation – Compact and silent design perfect for small technical rooms and noise-sensitive residential installations

✅ Salt Water & Sea Water Compatible – AISI 316 stainless steel mechanical seal resists corrosion from salt chlorination systems and marine environments

✅ Three Phase Power (230/400V) – Reliable three-phase operation delivers consistent performance with lower running current (2.45/1.4A)

✅ Made in EU – European manufacturing ensures quality control and compliance with industry standards

✅ 3-Year Manufacturer Warranty – Extended coverage provides long-term peace of mind for your investment

✅ Compact Design – Optimised footprint suits small plant rooms and underground equipment boxes where space is limited

✅ Quick-Seal Lid with Wing Nuts – Tool-free access to strainer basket simplifies routine cleaning and maintenance

✅ Large 1.75L Prefilter Basket – Generous capacity reduces cleaning frequency while protecting the pump from debris

✅ Smart Retrofit Kit Available – MPRK kit enables easy replacement of Astral Sena, Espa Silen I and Iris pumps on existing installations

🔧 Technical Specifications

Specification	Detail
Model	OK 51T1 (Ondina-OK)
Product Code	010211250100
Motor Power Output (P2)	368 W (0.50 HP)
Power Input (P1)	580 W
Electrical Phase	Three Phase (230/400V AC)
Frequency	50 Hz
Current Draw	2.45 / 1.4 A
Flow Rate @ 8m Head	8.5 m³/h
Motor Speed	2,850 rpm
Motor Class	Class F
Protection Rating	IP55
Motor Efficiency	IE2 ✓
Connection	Threaded 1½”
Maximum Water Temperature	50°C
Maximum Pressure	2.5 bar
Mechanical Seal	AISI 316 Stainless Steel
Salt Water Compatible	Yes ✓
Housing Material	PP + Fibre Glass
Impeller Material	Noryl®
Strainer Material	PP
Lid Material	SAN®
Prefilter Capacity	1.75 Litres
Dimension A (Length)	500 mm
Packing Size	310 × 250 × 510 mm
Weight	9 kg
Recommended Pool Size	Up to 75 m³
Warranty	3 Years
Country of Manufacture	EU 🇪🇺

💰 Usage Costs & Running Expenses

Understanding your pump’s operating costs helps with budgeting and comparing options. Here’s a detailed breakdown for the Ondina-OK 51T1:

📊 Annual Running Cost Calculation

Power input (P1): 0.58 kW
UK electricity rate: £0.2769 per kWh (Ofgem Price Cap Q1 2026)

🏊 Scenario 1: Seasonal Pool Use (April – September)

Typical UK outdoor pool operating during warmer months.

Parameter	Value
Daily runtime	8 hours
Season length	180 days (6 months)
Annual operating hours	1,440 hours

📈 Calculation:

• Energy consumed: 0.58 kW × 1,440 hours = 835.2 kWh/year
• ✅ Annual cost: 835.2 × £0.2769 = £231.27

💷 Under £235 per year for complete seasonal pool circulation!

🔥 Scenario 2: Year-Round Heated/Indoor Pool

Indoor or heated pools requiring continuous circulation throughout the year.

Parameter	Value
Daily runtime	10 hours
Operating days	365 days
Annual operating hours	3,650 hours

📈 Calculation:

• Energy consumed: 0.58 kW × 3,650 hours = 2,117 kWh/year
• ✅ Annual cost: 2,117 × £0.2769 = £586.20

💷 Under £590 per year for continuous year-round operation!

☀️ Scenario 3: Light Use / Small Pool

Smaller pools or reduced filtration requirements.

Parameter	Value
Daily runtime	6 hours
Season length	150 days (5 months)
Annual operating hours	900 hours

📈 Calculation:

• Energy consumed: 0.58 kW × 900 hours = 522 kWh/year
• ✅ Annual cost: 522 × £0.2769 = £144.54

💷 Under £145 per year for light seasonal use!

⚡ Efficiency Comparison: Ondina-OK Range

Model	Phase	HP	P1 (kW)	Flow @ 8m	Annual Cost (1,440 hrs)
OK 33M	Single	0.33	0.45	7 m³/h	£179.43
OK 51M	Single	0.50	0.58	8.5 m³/h	£231.27
✅ OK 51T1	Three	0.50	0.58	8.5 m³/h	£231.27
OK 71M	Single	0.75	0.75	11.9 m³/h	£299.06
OK 71T1	Three	0.75	0.75	11.9 m³/h	£299.06
OK 100M	Single	1.00	1.00	17.2 m³/h	£398.74

Calculations based on 1,440 hours seasonal use at £0.2769/kWh

💵 The OK 51T1 offers excellent balance – sufficient flow for most residential pools while keeping running costs impressively low!

🔋 Three Phase vs Single Phase Advantages

Three-phase motors like the OK 51T1 offer advantages over single-phase equivalents:

Benefit	Detail
⚡ Lower current draw	2.45/1.4A vs 3.5A single-phase
🔄 Smoother operation	More consistent power delivery
📉 Reduced electrical stress	Balanced load across phases
🔧 Longer motor life	Less heat generation, reduced wear

🎯 Real World Examples & Applications

🏊‍♂️ Small to Medium Domestic Pools (25-75m³)

The OK 51T1 is perfectly sized for typical UK garden pools. With 8.5m³/h flow rate, it can turn over a 34m³ pool approximately every 4 hours – meeting the recommended 2-3 turnovers daily for optimal water quality. The compact 500mm length fits easily into standard pool plant rooms.

🏠 Space-Constrained Installations

For properties with limited plant room space or underground equipment chambers, the Ondina-OK’s compact footprint and quiet operation make it an ideal choice. The quick-seal wing nut lid allows easy maintenance access even in tight spaces.

🌊 Salt Water Pool Systems

The AISI 316 stainless steel mechanical seal is specifically designed for salt water compatibility. Whether using salt chlorination or operating near coastal/marine environments, the OK 51T1 resists corrosion that would damage standard pumps.

🔄 Retrofit & Replacement Projects

The Smart Retrofit Kit (MPRK) enables straightforward replacement of older Astral Sena, Espa Silen I, and Iris pumps. Kit includes mounting base, fixing screws, threaded adaptors, and O-rings – minimising pipework modifications on existing installations.

🏢 Small Commercial Applications

Holiday lets, B&Bs, and small leisure facilities benefit from the three-phase reliability and quiet operation. The IE2 efficiency rating helps manage operating costs while the 3-year warranty provides commercial peace of mind.

💡 Cost Savings Examples

📍 Scenario: Upgrading from an Older 0.75kW Pump

Many older installations feature oversized or inefficient pumps. Here’s what switching to the OK 51T1 could save:

	❌ Old 0.75kW Pump	✅ Ondina-OK 51T1
Power consumption (P1)	0.75 kW	0.58 kW
Seasonal hours (1,440)	1,080 kWh	835.2 kWh
Annual electricity cost	£299.06	£231.27
Annual Saving	—	💰 £67.79

📈 Over 10 years: £67.79 × 10 = £677.90 in reduced electricity bills!

📍 Scenario: Choosing OK 51T1 vs Larger OK 71T1

Right-sizing your pump saves money. For a 35m³ pool, the OK 51T1 provides adequate circulation:

	❌ OK 71T1 (Oversized)	✅ OK 51T1 (Right-sized)
Power consumption (P1)	0.75 kW	0.58 kW
Seasonal hours (1,440)	1,080 kWh	835.2 kWh
Annual cost	£299.06	£231.27
Annual Saving	—	💰 £67.79

📊 Over 5 years: £67.79 × 5 = £338.95 saved by choosing the correct pump size!

📍 Scenario: Year-Round Indoor Pool Comparison

For heated indoor pools running continuously:

	❌ 1.0kW Pump	✅ Ondina-OK 51T1
Power consumption (P1)	1.0 kW	0.58 kW
Annual hours (3,650)	3,650 kWh	2,117 kWh
Annual cost	£1,010.69	£586.20
Annual Saving	—	💷 £424.49

⏱️ Payback period: Potential to recover pump cost through energy savings in under 1 year!

📥 Downloads & Resources

📄 Kripsol Ondina-OK Technical Datasheet (PDF) – Complete specifications, performance curves and dimensional drawings

🔧 Smart Retrofit Kit (MPRK)

Easily replace old pumps on existing installations without major pipework changes:

Item	Pumps to Replace	Kit Contents
MPRK	Astral Sena, Espa Silen I, Iris	Smart Base (1), Fixing Screws (3), Short Threaded Adaptor (2), Long Threaded Adaptor (1), O-rings (4)

Kit enables quick swap-out of common pump brands with minimal modification

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🏆 Why Choose This Pump

✅ IE2 High Efficiency Motor – Exceeds minimum efficiency standards, reducing energy consumption and operating costs

✅ Compact & Silent Design – Perfect for small plant rooms, underground chambers, and noise-sensitive locations

✅ Full Salt Water Compatibility – AISI 316 mechanical seal handles salt chlorination and marine environments without corrosion

✅ Three Phase Reliability – Smooth, balanced operation with lower current draw (2.45/1.4A) extends motor lifespan

✅ EU Manufacturing Quality – Built to European standards with quality materials throughout

✅ 3-Year Warranty Confidence – Extended manufacturer coverage demonstrates reliability commitment

✅ Easy Maintenance Access – Quick-seal wing nut lid and large 1.75L prefilter simplify routine cleaning

✅ Ideal Pool Size Match – Designed for residential pools up to 75m³

✨ Summary

The Kripsol Ondina-OK 51T1 delivers efficient, quiet pool circulation in a compact package designed for space-constrained installations. With its IE2 high-efficiency three-phase motor, AISI 316 salt water compatible seal, and EU manufacturing quality, this pump provides reliable performance for small to medium residential pools up to 75m³ at running costs under £235 per year for typical seasonal use. The 3-year warranty, quick-seal maintenance access, and smart retrofit compatibility make it an excellent choice for new builds or upgrading existing systems. Compact, silent, and efficient – the OK 51T1 ticks all the boxes for discerning pool owners.