Astralpool Seal Plate - CTX Series 2, Aug 2014 40098
Astralpool Seal Plate - CTX Series 2, Aug 2014 40098 is temporarily out of stock and will ship as soon as it's available.
Don't Guess - Ask Us!
Don't Guess - Ask Us!
Not sure if it’s the right part? Send us a message and a photo of what you’re replacing, or what you need, and we’ll help make sure you get the right part the first time.
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Delivery and Shipping Info*
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Astralpool Seal Plate - CTX Series 2, Aug 2014 40098
Astralpool Seal Plate - CTX Series 2, Aug 2014 40098 is temporarily out of stock and will ship as soon as it's available.
Astralpool Seal Plate - CTX / Viron Series 2, Aug 2014 40098
This is the genuine Astralpool Series 2 seal plate, part number 40098 (black). The seal plate sits between the wet end and the motor, carrying the mechanical seal and sealing the water chamber from the motor shaft. This is the new-style seal plate introduced August 2014, used on CTX and Viron pumps from then until the November 2020 MkII revision.
- Physically Stocked, unlike most "drop-shipping" websites.
- Shipped from VIC, NSW, WA, QLD
Three Generations — Order the Right One
Astralpool changed the seal plate twice, alongside the wet end. The seal plate and volute must come from the same generation as your pump, or they will not bolt up and seal correctly:
| Generation | Seal plate | Matching volute |
|---|---|---|
| Series 1 — old style, pre-Aug 2014 | 4009002 | 4007502 |
| Series 2 — Aug 2014 to 2020 | 40098 — this product | 40097 |
| MkII — Nov 2020 onwards | SP40030 | SP40031 |
If you are not sure which generation your pump is, send us a photo of the pump and its data plate and we will identify it.
Fit the Mechanical Seal at the Same Time
Whenever the seal plate comes out, the mechanical seal is disturbed. Always fit a new mechanical seal (75508 / PS3868) and a new seal plate o-ring (70022) with a seal plate — reusing either is the most common cause of a leak straight after the job.
What the Seal Plate Is
The seal plate bolts to the front of the motor and closes off the back of the wet end. The stationary half of the mechanical seal presses into it, and the rotating half sits on the impeller hub. It is replaced when the seal seat is scored, when the plate is cracked, or when a previous seal has failed and worn the face.
Related Series 2 Parts
- 40097 — volute / wet end, Series 2 (buy here)
- 75508 / PS3868 — mechanical seal, BX / TX / CX / E / CTX (buy here)
- 70022 — seal plate o-ring, new style Aug 2014 onwards
- 78772 — seal plate to wet end bolts (x6)
- Impeller — sized to your CTX model, see the CTX impeller range
Frequently Asked Questions
How do I know if I need the Series 2 seal plate?
Series 2 was fitted from August 2014 until the November 2020 MkII change, matched to the 40097 wet end. If unsure, send us a photo of the data plate.
Should I replace the mechanical seal too?
Yes, always. The seal is disturbed as soon as the plate comes off, and reused seal faces are the most common cause of a leak after the job. Fit a new 75508 seal and 70022 o-ring.
Can I fit a MkII seal plate instead?
No. The generations are not cross-compatible as a mix. The seal plate, volute and o-rings changed together.
Is this a genuine Astralpool part?
Yes. We are an authorised Astralpool and Fluidra dealer and warranty agent.
Manufacturer Catalogues, Diagrams & Part Numbers
Need exploded views, spare part numbers, product numbers or diagrams? See the manufacturer catalogue: Astralpool Catalogue 2026
Before ordering: confirm this part is correct for your pump. Use the catalogue above, seek professional assistance, or contact us with photos of your existing part, model details, serial numbers and any labels. As with all products, this must be diagnosed and fitted by a qualified and experienced person. This is a special-order item.
Common search terms: Astralpool 40098, CTX seal plate Series 2, CTX seal plate black, Viron seal plate, Astral Hurlcon seal plate Aug 2014.
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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