Calorex V-PAC 22 Top Outlet Inverter Pool Heat Pump 24.4kW | Extended Summer Season | VPT22ALX 🌊

Transform your pool experience with Britain’s most advanced inverter heat pump technology. The Calorex V-PAC 22 delivers powerful, whisper-quiet heating from April through October, ensuring your pool stays perfectly warm throughout the extended summer season. With industry-leading efficiency and intelligent inverter control, you’ll enjoy lower running costs and exceptional performance designed specifically for the UK climate.

Why Choose the V-PAC 22? ✅

The V-PAC 22 represents the pinnacle of British-engineered pool heating technology. Unlike traditional on/off heat pumps that waste energy and create noise, this intelligent inverter system dynamically adjusts its output to match your pool’s exact heating requirements. The result? Up to 60% energy savings, near-silent operation, and consistent water temperatures that make every swim perfect.

Proudly designed by Dantherm in the UK for the UK climate, this heat pump understands British weather patterns and delivers reliable performance when you need it most. From early spring sunshine to late autumn evenings, the V-PAC 22 extends your swimming season by months, not weeks.

📄 Downloads & Technical Documentation

Owner’s & Installation Manual (opens in new tab) Download Complete V-PAC Manual – PDF Comprehensive 31-page guide covering installation procedures, electrical specifications, operating instructions, maintenance schedules, troubleshooting, winterisation procedures, and warranty conditions for VPT12ALX, VPT16ALX, and VPT22ALX models.

• Product Brochure EN

💡 Installation Note: Professional installation recommended. Comprehensive manual includes wiring diagrams, plumbing requirements, and airflow specifications to ensure optimal performance.

🔥 Key Features & Benefits

Revolutionary Inverter Technology

Unlike conventional pool heaters that constantly cycle on and off, the V-PAC 22’s stepless DC inverter compressor provides infinitely variable output control. This means:

• Maximum Efficiency: Save up to 60% on running costs compared to traditional heat pumps
• Whisper-Quiet Performance: Enjoy 9-11 dB(A) reduction compared to standard heat pumps – that’s quieter than a whisper
• Smooth Operation: Eliminates disruptive power surges and inrush currents that can trip breakers
• Extended Equipment Life: Gentle operation reduces wear and tear on components

Eco-Friendly R32 Refrigerant ♻️

Environmental responsibility meets exceptional performance. The V-PAC 22 uses R32 refrigerant with a Global Warming Potential (GWP) of just 675 – significantly lower than older refrigerants. Fully F-Gas compliant, this forward-thinking choice ensures your pool heating meets current and future environmental regulations without compromising heating power.

Powerful Yet Compact Design

Don’t let the modest footprint fool you – this unit packs 24.4kW of heating capacity into a surprisingly compact design that:

• Saves valuable outdoor space with efficient vertical configuration
• Complies with permitted development rights – no planning permission needed
• Features robust ABS casing that withstands British weather year after year
• Measures just 745mm x 752mm x 967mm – fits where larger units can’t

Intelligent Multi-Mode Operation 🎯

Powerful Mode – 100% heating capacity for rapid pool heat-up. Ideal for initial pool warming or after cooler periods.

Smart Mode – Intelligent optimization from 25-100% capacity. Perfect for everyday temperature maintenance with maximum efficiency.

Silent Mode – 50% heating capacity with ultra-quiet operation. Ideal for night-time heating without disturbing you or your neighbours.

Extended Operating Range

Designed for the UK’s unpredictable weather, the V-PAC 22 operates efficiently in ambient temperatures from -5°C to +43°C. This extended range means reliable heating from early spring through late autumn, giving you months of additional swimming time.

📊 Complete Technical Specifications

Specification	VPT22ALX Detail
Model Number	VPT22ALX
Type	Top outlet vertical inverter heat pump
Phase	Single-phase 230V 50Hz
Operating Season	Extended summer (April – October)
Heating Capacity (27°C air/27°C water)	24.4 kW
Heating Capacity (15°C air/26°C water)	17.8 kW
COP Range (27°C conditions)	13.5 – 5.14
Average COP at 50% Speed	8.8
COP Range (15°C conditions)	6.2 – 4.14
Average COP at 50% Speed (15°C)	4.7
Rated Input Power	0.75 – 4.75 kW
Rated Input Current	3.45 – 19.6 A
Maximum Input Current	24.5 A
Recommended Fuse/MCB	32A (Type C MCB or aM fuse)
Recommended RCD	30mA Type F
Sound Level at 10m	<30 dB(A)
Operating Air Temperature Range	-5°C to +43°C
Water Temperature Setting Range (Heating)	18°C – 40°C
Water Temperature Setting Range (Cooling)	12°C – 30°C
Recommended Water Flow Rate	8.98 m³/h
Water Connections	1½” BSP and 50mm adaptors included
Refrigerant Type	R32 (Low GWP – 675)
Refrigerant Charge	1.7 kg
Minimum Installation Area	24.6 m² (due to R32 safety requirements)
Casing Material	ABS (weather-resistant)
Dimensions (L x W x H)	745 x 752 x 967 mm
Net Weight	95 kg
Warranty	5 years (on-site parts and labour)
Manufacturer	Dantherm (Calorex brand)

🏊 Pool Sizing & Suitability Guide

Recommended Pool Volumes

Pool Volume	Suitability	Heat-Up Performance
Up to 40m³ (40,000L)	✅ Excellent	Rapid heat-up, ideal sizing
40-60m³ (60,000L)	✅ Very Good	Good heat-up times, efficient maintenance
60-80m³ (80,000L)	✅ Good	Adequate for season extension
80-100m³ (100,000L)	⚠️ Marginal	Slower heat-up, best for maintained temperature
Over 100m³	❌ Consider larger model	Insufficient for timely heat-up

💡 Pool Volume Calculation:

• Rectangular pool: Length (m) × Width (m) × Average Depth (m) = Volume (m³)
• Round pool: π × Radius² × Average Depth = Volume (m³)
• Oval pool: π × Length/2 × Width/2 × Average Depth = Volume (m³)

⏱️ Estimated Heat-Up Times

Understanding how quickly your pool will warm helps you plan your swimming schedule. These estimates show typical heat-up times under different conditions using the V-PAC 22’s 17.8kW average output at 15°C ambient temperature (typical UK spring/autumn conditions).

Heat-Up Time Calculator

Formula Used: Time (hours) = (Pool Volume m³ × Temperature Rise °C × 1.16) ÷ Heat Pump kW

Pool Volume	5°C Rise	8°C Rise	10°C Rise	12°C Rise
30m³	9.8 hrs	15.6 hrs	19.5 hrs	23.4 hrs
40m³	13.0 hrs	20.8 hrs	26.0 hrs	31.2 hrs
50m³	16.3 hrs	26.1 hrs	32.6 hrs	39.1 hrs
60m³	19.6 hrs	31.3 hrs	39.1 hrs	46.9 hrs
70m³	22.8 hrs	36.5 hrs	45.7 hrs	54.8 hrs
80m³	26.1 hrs	41.7 hrs	52.2 hrs	62.6 hrs

Real-World Heating Scenarios

Example 1: 8m × 4m × 1.5m Pool (48m³)

• From 18°C to 26°C (8°C rise)
• Estimated time: 25 hours continuous operation
• Practical approach: Run for 2-3 days to achieve target temperature

Example 2: 10m × 5m × 1.5m Pool (75m³)

• From 15°C to 25°C (10°C rise)
• Estimated time: 49 hours continuous operation
• Practical approach: Initial heat-up over 3-4 days, then maintain

⚠️ Important Disclaimers:

• Estimates based on 15°C ambient temperature and 17.8kW heat output
• Actual times vary based on ambient temperature, wind, pool cover usage, and starting water temperature
• Using a pool cover can reduce heat-up time by 40-60%
• Warmer ambient temperatures improve heat pump efficiency and reduce times
• Heat loss during heating extends overall time required

💰 Running Cost Comparison vs. Alternative Heating

Annual Running Cost Estimates (50m³ Pool, April-October Season)

Heating Method	Typical COP/Efficiency	Estimated Annual Cost*
V-PAC 22 Heat Pump	COP 6-9	£400-£600 ✅
Traditional On/Off Heat Pump	COP 4-5	£750-£950
Electric Pool Heater (12kW)	COP 1	£2,200-£2,800
Gas Pool Heater	80-85% efficiency	£1,400-£1,800
Oil Pool Heater	75-80% efficiency	£1,600-£2,100

*Based on maintaining 26-28°C pool temperature during extended season, with pool cover, average UK electricity rates £0.28/kWh (2025), gas £0.10/kWh, and oil £0.90/litre. Your actual costs will vary based on usage patterns, ambient temperatures, and energy prices.

Inverter vs. Traditional Heat Pump Savings

With a COP of 8.8 at optimal conditions, the V-PAC 22 is approximately 50-75% more efficient than traditional on/off heat pumps. Over a typical 7-month swimming season:

• Potential annual savings: £200-£400 vs. traditional heat pump
• Potential annual savings: £1,600-£2,200 vs. electric heater
• Payback period: Typically 3-5 years through energy savings alone

🔧 Installation Requirements

Electrical Specifications

• Supply: 230V, Single-phase, 50Hz
• Fuse/MCB: 32A Type C MCB or aM fuse (H.R.C. fuses recommended)
• RCD: 30mA Type F (must protect heat pump circuit only)
• Isolator: Must disconnect all poles, within 2m and line of sight, minimum 3mm air gap
• Voltage Range: Minimum 207V, Maximum 253V (at heat pump during operation)
• Frequency: 47.5-52.5 Hz
• Cable Entry: Two cable entry points provided

⚠️ Critical: All electrical work must comply with current IEE regulations or local codes. Professional installation by qualified electrician required.

Plumbing Requirements

• Water Connections: 1½” BSP (supplied with 50mm adaptors)
• Flow Rate: 8.98 m³/h (recommended)
• Bypass Valve: Must be installed to achieve correct flow rate
• Non-Return Valve: Required to prevent backflow
• Condensate Drain: Must be connected to waste or soakaway
• Winterisation Provision: Drain valves and access points required
• Pipework Support: All pipework must be independently supported

Installation Tip: Install heat pump after pool filter and before any chemical dosing equipment or auxiliary heaters.

Location & Airflow Requirements

Minimum Clearances:

• Front (discharge): 3,000mm clear space
• Sides: 500mm from obstructions
• Rear: 500mm from obstructions
• Top: 500mm clearance

Installation Location Options:

• Outdoor installation: No area restrictions (unlimited air supply)
• Indoor/plant room: Minimum floor area 24.6 m² required (R32 safety regulations)
• Pool hall proximity: Must be at least 3.5m from pool edge (electrical safety)

Airflow Considerations:

• Must have access to fresh air – recirculation significantly reduces performance
• Free discharge area required: 0.220 m²
• If ducted, ensure adequate inlet and outlet grilles
• Never install in enclosed space without adequate ventilation
• Plant room must open to outside air supply

Mounting

• Fix to solid concrete base using M10 bolts (minimum)
• Use supplied rubber mounting pads to reduce vibration transmission
• Ensure base is level and can support 95kg + water in heat exchanger
• Allow access for maintenance and winterisation

🎛️ Advanced Control Features

Easy-to-Use LED Control Panel

• Large digital display shows water temperature and operating status
• Intuitive button controls for temperature adjustment and mode selection
• Visual indicators for heating, cooling, timer, and operating mode
• Real-time diagnostics accessible through service menu
• Clock and timer functions for automated operation

Programmable Timer

Set daily ON and OFF times to:

• Heat your pool during cheaper night-time electricity rates
• Maintain temperature during peak usage times
• Reduce running costs with smart scheduling
• Automatically prepare pool before you wake up

Pool Pump Override (P1/P2 Terminals)

When connected, the heat pump can override your filter pump timeclock to:

• Run circulation pump only when heating is needed
• Sample water temperature periodically
• Reduce filter pump energy consumption
• Maximize heating efficiency while minimizing pump run time

Temperature Settings

• Heating Range: 18°C – 40°C (precise 1°C increments)
• Cooling Range: 12°C – 30°C (for hot summer days)
• Automatic defrost prevents ice build-up in cold conditions
• Manual defrost trigger available when needed

🛡️ Protection Systems & Safety Features

Built-In Protection Codes

• Er 03: No water flow protection (prevents compressor damage)
• Er 04: Automatic frost protection (keeps unit safe during standby)
• Er 21: Ambient temperature protection (outside operating range)
• Er 27: Excessive temperature difference protection (flow rate issue)

Fault Detection System

Advanced microprocessor monitors:

• High and low refrigerant pressure
• Compressor exhaust gas temperature
• Water inlet and outlet temperatures
• Evaporator coil temperature
• Condenser coil temperature
• Fan motor operation
• Inverter module communication
• DC current protection

All faults are displayed on the control panel with specific error codes for rapid diagnosis and resolution.

R32 Refrigerant Safety

The V-PAC 22 uses R32 refrigerant (safety classification A2L – low toxicity, lower flammability). While R32 is extremely difficult to ignite, the installation includes multiple safety measures:

• Minimum area requirement ensures safe refrigerant concentration even in event of leak
• Installation guidance complies with EN378-1:2016 standards
• Proper ventilation eliminates possibility of flammable atmosphere
• Professional servicing only by F-Gas registered engineers

🧰 Maintenance & Winterisation

Routine Maintenance (Every Season)

• Clean air intake fins with soft brush to maintain airflow
• Check water connections for leaks or loosening
• Inspect electrical connections for corrosion or damage
• Test condensate drain is flowing freely
• Verify pool water chemistry is within specification (see warranty conditions)
• Check bolts and mounting are secure

Water Chemistry Requirements (Critical for Warranty)

Parameter	Required Range
pH	7.2 – 7.8
Total Alkalinity	80 – 120 ppm
Total Hardness	150 – 250 ppm
Total Dissolved Solids	Max 1,000 ppm
Maximum Salt Content	Max 35,000 ppm
Free Chlorine (Domestic)	1 – 2 ppm
Free Chlorine (Commercial)	3 – 6 ppm
Bromine	2 – 5 ppm
Baquacil	25 – 50 ppm
Maximum Copper Content	1 ppm

⚠️ Super-chlorination: Maximum 30ppm for 24 hours only

Winterisation Procedure (Essential)

When: Before first frost or when pool closing for season

Critical Steps:

1. Switch off electrical supply and remove fuses (store safely away from unit)
2. Isolate and switch off pool circulation pump
3. Open drain valve or disconnect water piping
4. Remove condenser drain cover
5. Flush heat exchanger with CLEAN TAP WATER (not pool water) for minimum 10 minutes
6. Allow to drain completely
7. Cover water connections with plastic bags secured with elastic bands
8. Spray electrical enclosure interior with WD-40 or moisture repellent
9. Protect outdoor units with breathable cover (bespoke winter cover available separately)

⚠️ Warranty Warning: Failure to properly winterise will void warranty if frost or corrosion damage occurs

Spring Start-Up

1. Remove winter cover and inspect unit
2. Clean air intake fins with soft brush
3. Remove plastic bags from water connections
4. Reconnect water piping or close drain valve
5. Start circulation pump and run for 15 minutes to establish flow and purge air
6. Replace fuses and restore power
7. Switch on heat pump and set desired temperature
8. Verify pool water chemistry is correct

✅ Comprehensive 5-Year Warranty

Industry-Leading Coverage

The V-PAC 22 comes with a no-nonsense, comprehensive 5-year parts and labour warranty – one of the best in the industry. This includes:

• On-site repairs by factory-trained technicians
• All parts covered – compressor, heat exchanger, controls, electronics
• Labour costs included – no hidden charges for service visits
• Nationwide coverage through Dantherm’s network of service agents
• Experienced support team backed by in-house technical expertise

Warranty Exclusions

To maintain warranty validity, ensure:

✅ Installation complies with manufacturer specifications ✅ Water chemistry maintained within required parameters ✅ Unit properly winterised if not in use during cold weather ✅ Adequate water flow maintained (8.98 m³/h recommended) ✅ Correct electrical supply (207-253V) ✅ Only authorised technicians perform repairs or modifications ✅ Adequate airflow maintained (no blocked grilles) ✅ Unit correctly sized for application

💡 Registration: Register your warranty online within 30 days of installation for full coverage activation.

🌟 Frequently Asked Questions

Q1: How much will the V-PAC 22 cost to run?

A: Running costs depend on your pool size, desired temperature, and ambient conditions. For a typical 50m³ pool during April-October season, expect £400-£600 in electricity costs (at 2025 rates). Using a pool cover can reduce this by 40-60%. The inverter technology makes this heat pump 50-75% more efficient than traditional on/off models, saving £200-£400 annually compared to older heat pumps.

Q2: Can I heat my pool in winter with this model?

A: The V-PAC 22 is designed for extended summer season use (April-October) and operates efficiently down to -5°C ambient temperature. However, winter heating efficiency drops significantly below 5°C. For year-round heating, consider the I-PAC range designed for all-season use. The V-PAC 22 must be properly winterised if not in use during cold weather to prevent frost damage.

Q3: How loud is the V-PAC 22 in operation?

A: Exceptionally quiet! At just <30 dB(A) at 10 metres, it’s quieter than a whisper. The Silent Mode reduces sound even further to 50% capacity. The inverter technology provides 9-11 dB(A) sound reduction compared to traditional on/off heat pumps. You can run it overnight without disturbing you or your neighbours.

Q4: Do I need planning permission to install this heat pump?

A: Generally no. The V-PAC 22’s compact design complies with permitted development rights in the UK, meaning most installations don’t require planning permission. However, always check with your local planning authority, especially if you live in a conservation area, listed building, or have specific property restrictions.

Q5: What’s the difference between the V-PAC and I-PAC ranges?

A:

• V-PAC (this model): Top outlet design, extended season (April-Oct), operates -5°C to +43°C, ABS casing, extended summer use
• I-PAC: Side outlet design, all-year operation, operates -15°C to +43°C, aluminium alloy casing, includes Wi-Fi control

Choose V-PAC for cost-effective seasonal heating or I-PAC for year-round swimming.

Q6: Can this heat pump also cool my pool in very hot weather?

A: Yes! The V-PAC 22 has multi-function operation including heat/cool mode. During extremely hot weather (above 30°C), you can switch to cooling mode to reduce water temperature to a comfortable 24-28°C. This is particularly useful for indoor pools or during UK heatwaves.

Q7: Will this heat pump work with my existing pool equipment?

A: Yes, the V-PAC 22 is compatible with virtually all pool systems. It connects to standard 1½” BSP or 50mm pipework and works with any brand of filter, pump, or sanitisation system. Install the heat pump after the filter and before any chemical dosing equipment. Your installer may need to add a bypass valve to achieve the recommended 8.98 m³/h flow rate.

Q8: What size pool is this heat pump suitable for?

A: The 24.4kW V-PAC 22 is ideal for pools up to 60m³ (60,000 litres). For larger pools up to 80m³, it will maintain temperature effectively but initial heat-up will be slower. Smaller pools (30-40m³) will heat quickly and maintain temperature easily. Pool covers dramatically improve performance for all sizes.

Q9: How long is the warranty and what does it cover?

A: The V-PAC 22 comes with an industry-leading 5-year comprehensive parts and labour warranty covering on-site repairs. This includes all components – compressor, heat exchanger, controls, and electronics. The warranty is backed by Dantherm’s nationwide network of service agents and experienced in-house technical team. Conditions apply – see warranty section for details.

Q10: Can I install this heat pump myself?

A: While physically possible for competent DIYers, professional installation is strongly recommended for several reasons:

• Electrical work must comply with IEE regulations (qualified electrician required)
• Correct sizing of MCB/RCD protection is critical
• Proper water flow rate must be achieved with bypass adjustment
• R32 refrigerant safety requires specific installation area and ventilation
• Professional installation may be required for warranty validation
• Incorrect installation can damage the unit or reduce efficiency by 50%+

Q11: What maintenance does the V-PAC 22 require?

A: Minimal! Annual maintenance includes:

• Clean air intake fins with soft brush
• Check water connections and electrical terminals
• Test condensate drain
• Verify pool water chemistry
• Inspect for any leaks or damage

Critical: Proper winterisation is essential to prevent frost damage (see winterisation section). Pool water chemistry must be maintained within specifications or warranty will be void.

Q12: Why does this model require a minimum 24.6m² area for indoor installation?

A: This is a safety requirement for R32 refrigerant used in the heat pump. R32 has an A2L safety classification (low toxicity, lower flammability). The 24.6m² minimum area ensures that even in the extremely unlikely event of a refrigerant leak, the concentration stays far below the lower flammability limit (as required by EN378-1:2016 standards). Outdoor installations automatically meet this requirement as outside space is unlimited.

🚚 What’s Included in the Box

✅ V-PAC 22 Heat Pump (VPT22ALX) – factory tested ✅ 2 × 1½” BSP water union connectors ✅ 2 × 50mm water union connectors
✅ Condensate drainage kit ✅ 4 × Rubber mounting pads (vibration isolation) ✅ Installation & user manual ✅ Warranty registration information

Not Included (Available Separately):

• Remote control panel kit (for indoor control)
• Winter protection cover (breathable, custom-fit)
• Bypass valve kit
• Isolation valves
• Water piping and connections
• Electrical supply cable and components

🎯 Summary: Why the V-PAC 22 is Your Best Choice

✅ Supreme Efficiency: Average COP of 8.8 means up to 60% energy savings ✅ Whisper-Quiet: <30 dB(A) at 10m – quieter than a library ✅ British Engineering: Designed by Dantherm specifically for UK climate ✅ Extended Season: Reliable operation April through October ✅ Eco-Friendly: R32 refrigerant with low GWP (675) ✅ Powerful: 24.4kW heating capacity for pools up to 60m³ ✅ Intelligent Control: Three operating modes for every situation ✅ Compact Design: Space-efficient footprint that complies with permitted development ✅ Comprehensive Warranty: 5 years parts and labour on-site coverage ✅ Multi-Function: Heat, heat/cool, or cool-only operation ✅ Proven Reliability: Trusted Calorex brand backed by Dantherm Group ✅ Professional Support: Nationwide service network and expert technical team

Transform your pool experience today with the V-PAC 22 – where British engineering excellence meets cutting-edge inverter technology. 🌊