The AstralPool CTX pool pump takes a mechanical seal for a 3/4″ shaft with carbon / ceramic faces. This aftermarket seal replaces Astral part 75508, which is the seal number listed for the CTX, and also Onga 700270. Measure the shaft or compare your old seal before fitting, because the shaft size and the stationary seat must match the pump.
How to tell you have an AstralPool CTX
Look at the motor label or the pump housing. The CTX range is marked with codes such as CTX280, CTX400 and CTX560, and some units carry Hurlcon branding as the Hurlcon CTX. If your label shows one of these, this is the seal listing to check against.
Signs the CTX seal has failed
A mechanical seal is two faces running against each other, one turning with the shaft and one fixed in the pump body, with a thin film of water between them. Over time the faces wear, chip or get scored by grit, and water starts to get past.
- Drips or a steady weep from the join between the wet end and the motor.
- White scale or rust stains running down from the seal area under the pump.
- Air bubbles or trouble holding prime, as a worn seal can let air in behind the impeller as well as letting water out.
- A noisy or rough-running motor after a long-term leak, which can point to water reaching the bearings.
Part numbers and other pumps that share the CTX seal
This seal replaces Astral 75508 and Onga 700270. The same 3/4″ seal is also listed for the AstralPool CX180, AstralPool CX240, AstralPool CX280, Filtermaster SB20, Filtermaster SB30, Onga Leisuretime LTP1100, Onga Pantera PPP750, Onga Pantera PPP1100 and Onga Pantera PPP1500. It is also listed to suit pumps such as the AstralPool BX, E-Series and TX, Poolrite Enduro and Quietline, Waterco Charger and a long list of Onga, Davey and Davies Classic models. The same seal is sold on its own as our 3/4″ pool pump seal.
Fitting the seal to an AstralPool CTX
Turn the power off at the isolator, close the valves and drain the pump before you start. Press the new stationary seat squarely into the housing, keeping the polished face clean and free of finger marks. Slide the spring half onto the shaft, refit the impeller and do not run the pump dry once it is back together, as the faces need water to stay cool. If you are already in there, the CTX service kit adds the run capacitor, and the rest of our range for this brand is on the AstralPool service kits page.
Before you order
Check the old part before fitting: match the size of your old seal.
Capacitor details for this pump: AstralPool CTX capacitor guide.