Quick overview
- Genuine Pentair Factory diffuser 355949Z, not an aftermarket substitute.
- Build date matters This diffuser is for SuperFlo VST pumps manufactured after 6/17/19, so check the pump before you order.
- Directs impeller flow The diffuser surrounds the impeller and turns its output into pressure the pump can push into the plumbing.
- A common cause of weak flow A cracked or worn diffuser lets water recirculate inside the housing instead of leaving the pump.
- Seats against the seal plate It sits between the impeller and the seal plate, so this is a job done with the pump opened up.
- Direct replacement Swaps for the original diffuser in the SuperFlo VST housing.
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Product details
The Pentair 355949Z is the genuine diffuser for SuperFlo VST pumps manufactured after 6/17/19.
Check the build date first
Pentair changed this part partway through the SuperFlo VST run. The listing covers pumps built after 6/17/19, and a pump made before that date takes a different diffuser. The build date is on the pump label, and it is worth confirming before you order rather than after the housing is open.
What it does
The diffuser is the shaped shroud that sits around the impeller. The impeller throws water outward, and the diffuser converts that motion into the pressure that pushes water through the filter and back to the pool. When it cracks or wears at the sealing face, water recirculates inside the pump instead of leaving it, and the symptom looks like weak flow with no obvious blockage.
Fitting
The diffuser sits between the impeller and the seal plate, so replacing it means opening the pump. It is a sensible time to look over the other wear parts you can see while the housing is apart.
| Brand | Pentair |
|---|---|
| Manufacturer part number | 355949Z |
| UPC | 788379885229 |
| Type | Pump diffuser |
| Fits | Pentair SuperFlo VST pumps manufactured after 6/17/19 |
| Shipping weight | 0.5 lb |
| Ships | Parcel |
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