Astralpool Gas Heater Gasket for MX, Viron, ICI, HiNRG - Tube Seals - 9 Pack
Astralpool Gas Heater Gasket for MX, Viron, ICI, HiNRG - Tube Seals - 9 Pack is temporarily out of stock and will ship as soon as it's available.
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Don't Guess - Ask Us!
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Astralpool Gas Heater Gasket for MX, Viron, ICI, HiNRG - Tube Seals...
Astralpool Gas Heater Gasket for MX, Viron, ICI, HiNRG - Tube Seals - 9 Pack is temporarily out of stock and will ship as soon as it's available.
AstralPool Gas Heater Heat Exchanger Tube Seal Gasket Kit – 9 Pack
Replacement heat exchanger tube seal gasket kit for AstralPool, Hurlcon, Viron, HiNRG, MX, ICI, WWDG and selected Jacuzzi gas pool and spa heaters.
This genuine AstralPool tube seal kit contains nine red heat exchanger tube gaskets. The seals fit around the heat exchanger tubes and are commonly replaced when repairing water leaks or rebuilding the heat exchanger assembly.
- Physically stocked, unlike most drop-shipping websites
- Shipped from locations in VIC, NSW, WA and QLD
Package Contents
- 9 × red heat exchanger tube seal gaskets
Important: These seals may fade from red to white when exposed to poor or unbalanced pool water chemistry. Colour fading does not necessarily indicate that a different gasket has been installed.
Compatible Gas Heaters
- AstralPool / Hurlcon MX: MX 125, MX 150, MX 200, MX 250, MX 300, MX 350 and MX 400
- AstralPool / Hurlcon Viron Evo: Viron Evo 250, Viron Evo 350 and Viron Evo 450
- AstralPool ICI: ICI 200 and ICI 400
- AstralPool / Hurlcon HiNRG: HiNRG 175, HiNRG 250 and HiNRG 450
- WWDG: WWDG 25 and WWDG 40
- Jacuzzi: J-HN250C and J-HN400C
Part Numbers
- Current AstralPool part number: 76121
- Previous or superseded part number: 76120
This product may also be described as an AstralPool tube seal, Hurlcon tube gasket, gas heater heat exchanger gasket, header tube seal, or heat exchanger O-ring kit.
Please confirm your heater model and required part number before ordering. Gas heater components should be inspected and installed by a suitably qualified technician.
Manufacturer Catalogues, Exploded Diagrams and Part Numbers
For exploded views, spare-part diagrams, heater model identification, product numbers and additional technical information, see our manufacturer catalogues:
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) |
|---|---|---|
| 1/2" | 15mm | ~21.2–21.5 mm |
| 3/4" | 20mm | ~26.6–26.9 mm |
| 1" | 25 mm | ~33.4–33.7 mm |
| 1.5" | 40 mm | ~48.1–48.4 mm |
| 2" | 50 mm | ~60.2–60.8 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. These are based on PVC Pressure Pipe AS/NZ 1477 Dimensions1.
- 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.
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).
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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76121