The Filtermaster SB20 service kit contains two parts: a mechanical seal for a 3/4″ shaft with carbon / ceramic faces, which replaces Onga 700270 and Astral 75508, and a 30 µF (30 uF / 30 MFD) 450 VAC CBB60 motor-run capacitor with core leads. The kit costs less than the seal and capacitor bought separately and has no bearings. Check that the µF printed on your old capacitor reads 30 before fitting.
What’s in the Filtermaster SB20 kit
Both parts are matched to the SB20 and each one is also sold individually if you only need one. Outside the kit, the seal also appears in our range as a general 3/4″ pool pump seal and the capacitor as a CBB60 30 µF 450 V run capacitor.
- SB20 mechanical seal: suits a 3/4″ shaft, carbon / ceramic faces, replaces Onga 700270 and Astral 75508. Supplied as the spring-loaded rotating half plus the stationary seat.
- SB20 run capacitor: 30 µF, 450 VAC, CBB60 motor-run body with core leads.
Why service the SB20 seal and capacitor together
Getting to a pump’s shaft seal is the bulk of the work: power off and isolated, wet end unbolted, impeller removed from the shaft. With the power already isolated and the pump open for the seal, swapping the run capacitor as well is a short extra step, and the job finishes with a new seal and a new capacitor fitted.
Both parts wear with age. A seal that has started to weep lets water creep along the shaft towards the motor bearings, while a capacitor that has lost capacity makes the motor work harder and run warmer. If the SB20 has been slow to start, or the old capacitor case looks swollen, changing it during the seal job saves coming back to the pump later.
Checking your SB20 parts before you order
Measure the shaft where the old seal sat and read the µF value printed on the side of the old capacitor. The kit capacitor is 30 µF; if yours shows a different number, contact us before ordering and we will help you match it. The Filtermaster SB30 kit uses the same seal, and other kits for this brand are on the Filtermaster service kits page. Unused parts can go back under our returns policy.
Before you order
Check the old parts before fitting: match the µF printed on your old capacitor and the size of your old seal.