Astralpool Lid Assembly - CTX, Viron XT
Astralpool Lid Assembly - CTX, Viron XT 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 Lid Assembly - CTX, Viron XT
Astralpool Lid Assembly - CTX, Viron XT is temporarily out of stock and will ship as soon as it's available.
Astralpool Lid Assembly - CTX, Viron XT SP40089
This is the genuine Astralpool complete lid assembly, part number SP40089 — the clear top, locking ring and o-ring together. It is the lid you look through to check the basket. Genuine OEM, not cheap generic — the aftermarket clear tops craze and yellow far faster.
- Physically Stocked, unlike most "drop-shipping" websites.
- Shipped from VIC, NSW, WA, QLD
Whole Lid — or Just the O-Ring?
This listing is the complete lid. If your clear top is fine and only the seal has perished, you can save money with the o-ring alone:
- The clear lid is cracked, crazed or cloudy — this part, the complete assembly SP40089.
- Only the seal has perished — the lid o-ring alone (70006).
Fits These Pumps
- Hurlcon & Astralpool CX: CX 180, CX 240, CX 280, CX 320
- Hurlcon & Astralpool TX: TX 1.0, TX 1.5, TX 2.0
- Astralpool CTX: CTX 180, 280, 360, 400, 500
- Astralpool E-Series: E 140, E 170, E 230
- Astralpool Viron XT: P320 XT, P520 XT
- Also suits Aquatight pumps with the same lid
Fitting Tip
The lid is designed to be hand-tight only — do not use tools. Clean the o-ring seat before fitting, since debris on the seat lets air into the suction side and stops the pump priming. Astralpool recommends checking and greasing the lid seal every three months.
Related Parts
- 70006 — lid o-ring alone (buy here)
- 40065 — basket (buy here)
- 75508 / PS3868 — mechanical seal (buy here)
- Impeller — sized to your model, see the CTX impeller range
Manufacturer Catalogues, Diagrams & Part Numbers
Need exploded views, spare part numbers, product numbers or diagrams? See the manufacturer catalogues: Astralpool Catalogue 2026 | Zodiac Catalogue 2026
Common search terms: Astralpool SP40089, 40089 lid, CTX pump lid, Viron XT lid, clear pump lid with locking ring, Astral Hurlcon pump lid assembly.
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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SP40089