Astralpool / Hurlcon HX 120 Gas Spa Heaters - HX120
Astralpool / Hurlcon HX 120 Gas Spa Heaters - HX120 - is backordered and will ship as soon as it is back in stock.
Delivery and Shipping
Delivery and Shipping
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The Astralpool HX120 (orignally the Hurlcon HX 120) is our most popular gas spa heater – and for good reason. With a time-tested design that’s remained virtually unchanged for over 25 years, it’s the best replacement for older MiniMax, HX 120, MX 125, MX 150, HiNRG 175, Raypak Spartan 131, and Raypak Premium 109, 127, 167 and similar models.
- We keep the HX120 in physical stock – ready to go.
- We stock more gas heater spare parts than anyone else.
- Contact us for pricing & availability.
About the Hurlcon / Astralpool HX 120 Spa Gas Heater:
Gas heating is the fastest way to heat your pool and spa. The HX gas pool and spa heater is the most effective solution available heating requirements. Made in Australia with electronic touch controls the HX 120 heater is ideal .
The HX120 has a heating output of around 25kW and can raise 1000L of water 20°C in approximately 1 hour. Some spas heat faster, and some slower.
Fits in the same footprint and plumbing as older, HX120 gas heaters, WX heaters, and most MiniMax / MM 120 heaters by Purex Hurlcon.
This is also the perfect heater for Spa & Swim Spa Gas conversions where speed of heating is important.
Features & Benefits:
- Less Maintenance and improved efficiency
- Electronic touch controls
- Available in Natural Gas and LPG models
- Heat on demand
- Electronic ignition
- Made in Australia
- Suitable for indoor and outdoor installations
- The HX 120 is equivalent to a 24kW electric heater, or up to a 35kW heat pump (in cold weather).
Time to Heat Water by 20°C (in a perfect world):
- 1000L = ~65min
- 1500L = ~78min
- 2000l = ~95 min
- 2500l = ~110min
Specifications:
- Height: 820mm
- Width: 390mm
- Depth: 515mm
- Weight: 25kg
- Water Flow: 150-300lpm. Fit bypass if over 300lpm.
- mJ Input: ~103mJ (see compliance label)
- Gas Consumption: ~2-2.2kg LPG/hr | ~2.6-3m³ Nat/hr
Care of your HX gas heater:
- HX heaters can last many years. We regularly service HX heaters made in the 1990s
- By far, the most important thing is Water Balance. Corrosion from low-pH & High Bromine / Chlorine is the biggest killer of gas heaters. The water can look Crystal Clear & Perfect, while it's eating away at at the Copper heat exchanger fittings. Bromine, Trichlor Tablets, and Dichlor powders lower water pH.
More Information & Downloads:
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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