Astralpool Lid O-Ring - CTX, E Series, Viron XT
Astralpool Lid O-Ring - CTX, E Series, Viron XT is temporarily out of stock and will ship as soon as it's available.
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Astralpool Lid O-Ring - CTX, E Series, Viron XT
Astralpool Lid O-Ring - CTX, E Series, Viron XT is temporarily out of stock and will ship as soon as it's available.
Astralpool Lid O-Ring - CTX, E-Series, Viron XT 70006
This is the genuine Astralpool pump lid o-ring, part number 70006 — the o-ring only, that seals the clear lid to the pump body. It is the single most common cause of a pump that will not prime or hold prime: a perished, flattened or dry lid o-ring lets air into the suction side. Marked yellow in the parts diagrams; originally supplied grey or black. Genuine OEM, not cheap generic.
- Physically Stocked, unlike most "drop-shipping" websites.
- Shipped from VIC, NSW, WA, QLD
O-Ring Only — or the Whole Lid?
This listing is the o-ring on its own. If your clear lid is cracked, crazed or no longer sealing at the rim, you need the complete lid instead:
- Just the seal has perished — this part, 70006.
- The clear lid itself is cracked or cloudy — the complete lid assembly (SP40089), which includes the clear top, locking ring and o-ring.
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
Maintenance Tip
Astralpool's own maintenance schedule calls for the lid o-ring to be checked every three months, cleaned and greased, and replaced if damaged. Clean the o-ring seat before refitting — debris on the seat leaks air just as a bad o-ring does. Do not overtighten the lid; it is designed to be hand-tight only.
Related Parts
- SP40089 — complete lid assembly with clear top, locking ring and o-ring (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 70006, CTX lid o-ring, Viron XT lid o-ring, pump lid seal, Astral Hurlcon lid o-ring, pump not priming air leak.
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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