1.5hp Madimack F400i - InverFlow Plus Pool Pump - Astralpool Retrofit
1.5hp Madimack F400i - InverFlow Plus Pool Pump - Astralpool Retrofit is backordered and will ship as soon as it is back in stock.
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Madimack InverFLOW PLUS F400i 1.5 HP Variable Speed Pool Pump
Premium energy-efficient variable speed pool pump that retrofits directly to many AstralPool, Hurlcon and Reltech installations – upgrade your old single-speed pump and start saving on power.
The Madimack InverFLOW PLUS F400i 1.5 HP Variable Speed Pool Pump delivers powerful flow rates for larger pools, high-demand systems and solar/heating setups, while still providing the massive energy savings of full inverter technology. Designed with retrofit plumbing positions that match popular AstralPool, Hurlcon and Reltech pumps, it replaces ageing single-speed units with minimal plumbing work required.
AstralPool, Hurlcon & Reltech Retrofit Compatibility
Retrofits plumbing for:
- AstralPool CTX 400
- Hurlcon TX 1.5
- Reltech
- Spapro XTC 1.5 & WWDG 1.5 XTC Pumps
This retrofit-ready design makes the F400i one of the easiest and most cost-effective upgrades for older, power-hungry pumps in medium-to-large pool systems.
Madimack Inverchlor salt & mineral chlorinators also retrofit AstralPool & Hurlcon chlorinators, allowing a complete, matched energy-efficient equipment upgrade.
Massive Energy Savings with Variable Speed Control
The F400i replaces large single-speed pumps that often run at full power all day. Using InverMAC variable speed technology, the F400i can slow down for filtration and general circulation while maintaining higher speeds only when needed (vacuuming, heating, water features).
- Cut electricity usage dramatically compared with older fixed-speed pumps
- Lower running costs year-round – especially during long filtration cycles
- Extend pump and equipment life by avoiding unnecessary high-speed use
- Enjoy quieter, cooler and more efficient operation
Powered by InverMAC Enhanced Inverter Technology
Madimack’s InverMAC motor platform is engineered specifically for pools, delivering powerful flow while maximising energy efficiency and reliability.
- Full inverter technology: Adjusts motor speed from roughly 30–100% depending on real-time demand.
- Ultra-quiet DC brushless motor: Operates from as low as 33 dB — extremely quiet for a high-output pump.
- Advanced centrifugal impeller: High-efficiency hydraulic design produces strong flow with reduced energy loss.
- Acoustic noise suppression: Engineered to minimise vibration and mechanical noise.
Smart, Connected & Easy to Operate
- Integrated Wi-Fi: Remote control and monitoring via compatible devices.
- Skimmer Mode: Intelligent surface-cleaning function for a clearer pool surface.
- Multiple custom speeds: Optimise flow for filtration, solar heating, cleaning or waterfalls.
- Dual-voltage compatible for flexible Australian installations.
- Industry-leading 5-year warranty for long-term confidence.
Why Upgrade to a Madimack InverFLOW PLUS F400i?
- Perfect for replacing AstralPool CTX400, Hurlcon TX1.5 and Reltech pumps without major plumbing changes
- Strong flow output suitable for medium-to-large pools and systems with heating
- Huge energy savings compared with older 1.5 HP single-speed pumps
- Ultra-quiet operation even at higher speeds
- Smart inverter control for better efficiency and easier day-to-day use
If your existing AstralPool, Hurlcon or Reltech 1.5 HP pump is noisy, inefficient or failing, the Madimack InverFLOW PLUS F400i offers a powerful, quieter and more cost-effective upgrade — complete with energy savings and modern smart-control technology.
In plumbing, named sizes are not the actual measurements. A pipe called “50mm” or “2"” does not measure 50 mm across. Instead, it follows nominal sizing, an internationally-standardised naming system.
Use the Outside Diameter (OD) to check your pipe against fittings. Below is a quick reference for common spa & pool pipe sizes:
| Imperial Name | Metric Name | Pipe Diameter (OD) |
|---|---|---|
| 1" | 25 mm | ~33.4–33.7 mm |
| 1.5" | 40 mm | ~48.1–48.4 mm |
| 2" | 50 mm | ~60.2–60.5 mm |
| 2.5" | 65 mm | ~75.2–75.5 mm |
These are nominal sizes and are designed to fit matching fittings — not to measure exactly what their name suggests.
Understanding Plumbing Sizes & Nominal Measurements
Plumbing sizes can be confusing. PVC and many other pipe systems use nominal sizes—the size is a name, not the exact measured dimension. This convention is used across most pool and spa systems so that pipes and fittings remain compatible.
Why pipe sizes don’t match the measurements
The Nominal Pipe Size (NPS) system standardises pipe dimensions so that pipes, fittings, valves, and accessories interoperate. Plumbers work with these nominal names every day, but DIYers can be tripped up if they try to match by a tape-measure alone.
How to Measure Pipe Correctly
-
Pipe size is identified by:
- The pipe’s Outside Diameter (OD).
- The fitting’s Inside Diameter (ID) (socket opening).
- Pipe Class / Schedule (e.g., Class 9, 12, 18 or Sch 40) relates to wall thickness and therefore the Internal Diameter (ID) and pressure rating.
- The outside diameter of a fitting is not useful (wall thickness varies by manufacturer).
PVC Pressure Pipe AS/NZ 1477 Dimensions1:
Common nominal sizes with typical outside diameters and indicative inside diameters by class.
| Imperial Name | Metric Name | Outside Diameter (OD) | Class 9 IDº | Class 12 IDº | Class 18 IDº |
|---|---|---|---|---|---|
| 1/2" | 15 mm | ~21.2–21.5 mm | 18.3 mm | 17.8 mm | |
| 3/4" | 20 mm | ~26.6–26.9 mm | 23.7 mm | 22.4 mm | |
| 1" | 25 mm | ~33.4–33.7 mm | 30.5 mm | 29.8 mm | 28.1 mm |
| 32 mm | ~42.1–42.4 mm | 38.5 mm | 37.5 mm | 35.4 mm | |
| 1.5" | 40 mm | ~48.1–48.4 mm | 45.2 mm | 44.1 mm | 42.8 mm |
| 2" | 50 mm | ~60.2–60.5 mm | 55.2 mm | 53.7 mm | 50.5 mm |
| 65 mm | ~75.2–75.5 mm | 68.9 mm | 67.0 mm | 63.2 mm | |
| 2.5" | ~73 mm |
- º Internal diameters vary slightly by manufacturer and class.
- 1 Not all pool/spa fittings match these dimensions exactly. Some do not follow Australian or international standards. Chinese spas may use proprietary fittings.
Hose & Tube Dimensions
Common flexible hose sizes used in pool/spa systems (approximate IDs).
| Imperial Name | Metric Name | Inside Diameter (ID) |
|---|---|---|
| 3/8" | 9–10 mm | ~9 mm |
| 3/4" | 19 mm | ~19 mm |
BSP – British Standard Pipe Thread Sizes
BSP thread names are also nominal. The thread OD will not equal the nominal name.
| BSP Thread Size Naming | Outside Diameter (mm / inch) | TPI |
|---|---|---|
| 1/16" BSP | 7.7 mm / 0.304" | 28 |
| 1/8" BSP | 9.7 mm / 0.383" | 28 |
| 1/4" BSP | 13.16 mm / 0.518" | 19 |
| 3/8" BSP | 16.66 mm / 0.656" | 19 |
| 1/2" BSP / 15 mm | 20.99 mm / 0.825" | 14 |
| 5/8" BSP | 22.99 mm / 0.902" | 14 |
| 3/4" BSP / 20 mm | 26.44 mm / 1.041" | 14 |
| 7/8" BSP | 30.20 mm / 1.189" | 14 |
| 1" BSP / 25 mm | 33.25 mm / 1.309" | 11 |
| 1-1/4" BSP | 41.91 mm / 1.650" | 11 |
| 1-1/2" BSP / 40 mm | 47.80 mm / 1.882" | 11 |
| 2" BSP / 50 mm | 59.61 mm / 2.347" | 11 |
| 2-1/4" BSP | 65.71 mm / 2.587" | 11 |
| 2-1/2" BSP | 75.18 mm / 2.960" | 11 |
| 3" BSP | 87.88 mm / 3.460" | 11 |
| 4" BSP | 113.03 mm / 4.450" | 11 |
| 5" BSP | 138.43 mm / 5.450" | 11 |
| 6" BSP | 163.83 mm / 6.450" | 11 |
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