AstralPool CX240 Mechanical Seal

The mechanical seal to suit the AstralPool CX240 is a 3/4″ shaft seal with carbon / ceramic faces. It replaces Astral 75508 and Onga 700270. The same seal is listed for the AstralPool CTX, CX180 and CX280, plus the Onga Pantera PPP750, PPP1100 and PPP1500, Onga Leisuretime LTP1100 and Filtermaster SB20 and SB30. Compare your old seal or measure the shaft before fitting.

AstralPool CX240 seal specification and part numbers

A mechanical seal has two halves: a spring-loaded face that turns with the shaft behind the impeller, and a stationary seat held in a rubber cup in the pump housing. The two lapped faces run against each other on a thin film of water, which is what keeps the water in the wet end and away from the motor. The same seal is also sold on its own as our 3/4″ pump seal.

• Shaft size: 3/4″
• Faces: carbon / ceramic
• Replaces: Astral 75508
• Replaces: Onga 700270

Which pumps use the same seal as the CX240

The CX240 seal is listed for the AstralPool CTX, AstralPool CX180, AstralPool CX280, Filtermaster SB20, Filtermaster SB30, Onga Leisuretime LTP1100, Onga Pantera PPP750, Onga Pantera PPP1100 and Onga Pantera PPP1500.

It is also listed for models that don’t have their own page here, including the AstralPool BX, CX, TX and E-Series, Poolrite Enduro, Cougar and Quietline, Waterco Charger, Spa-Quip Maxiflo and Onga Homemaster HM1.

Signs the CX240 seal has failed

Replace a leaking seal early. Water running along the shaft is a common reason pump motors end up with rusted bearings.

• Drips or a damp patch where the pump housing meets the motor
• A rust or white mineral trail running down below the motor end
• Trouble holding prime, which can come from air drawn in past a worn seal

Fitting notes

Turn off and isolate the power before opening the pump. Always fit both halves of the new seal; an old seat paired with a new face will usually leak. Keep the faces clean and dry, and don’t touch the lapped surfaces with your fingers. A smear of soapy water on the rubber cup helps the seat press in squarely. If you’re unsure of the size, measure the shaft where the seal sits, or send us a photo of your old seal through the contact page. Seals and kits for other models are on the AstralPool service kits page.

Before you order

Check the old part before fitting: match the size of your old seal.

What seal fits an AstralPool CX240?

The AstralPool CX240 takes a mechanical seal for a 3/4″ shaft with carbon / ceramic faces. This aftermarket seal replaces Astral 75508 and Onga 700270.

What part number does the AstralPool CX240 seal replace?

This seal replaces Astral 75508 and Onga 700270. If your old seal or its packet shows one of those numbers, this seal replaces it.

What shaft size is the CX240 mechanical seal?

The CX240 seal suits a 3/4″ shaft. Measure the shaft where the old seal sat if you want to confirm before ordering.

Does the AstralPool CX280 use the same seal as the CX240?

Yes. The AstralPool CX280, CX180 and CTX are all listed with the same 3/4″ carbon / ceramic seal as the CX240.

Can I replace just the seal on a CX240?

Yes. If the capacitor is also tired, the AstralPool CX240 service kit pairs this seal with a 20 µF run capacitor for less than buying both separately.

Is this seal made by AstralPool?

No. It is an aftermarket seal sold under the CapacitorsNZ brand to suit the AstralPool CX240, and it is not made or endorsed by AstralPool.

What if it doesn't fit?

If you're unsure, send us a photo of your old part and the pump's label before ordering.