
Quick overview
- Stainless steel Holds its tension on a wet equipment pad instead of rusting solid the way a plated washer does.
- Two required The assemblies this washer belongs to use a pair of them, so order accordingly.
- Split ring design The split bites into the nut face as it is tightened and resists backing off under pump vibration.
- Quarter inch size Sized for the 1/4 inch bolts and studs used on this equipment.
- Wide fitment Listed for Purex CFW cartridge filters, Purex 4000 Series molded DE filters, Pentair SM and SMBW 2000 Series backwash valves and Pentair EQ Series commercial pumps.
- Factory part number Purex 72172Z, the number to order by when you are matching hardware from a parts diagram.
Similar products
Other products people compare with this one.
Product details
Purex 72172Z is a 1/4 inch stainless steel split lock washer, and two are required wherever it is called out. It is small, cheap hardware that turns up on a lot of parts diagrams: Purex CFW cartridge filters, Purex 4000 Series molded DE filters, Pentair SM and SMBW 2000 Series backwash valves and Pentair EQ Series commercial pumps.
Why the washer matters
A split lock washer works by springing open against the nut as it is torqued down. The cut ends dig in and stop the fastener walking loose under the constant low frequency vibration a pump puts through a filter bank. Once the split has been crushed flat, or the washer has corroded, it no longer does that job and the nut it sits under starts to loosen between service visits.
Stainless, not plated
Stainless matters here more than it does indoors. Equipment pad hardware lives in splash, condensation and chlorinated air, and plated washers rust to the stud until the next technician has to cut them off. Replace the pair whenever you have the assembly apart rather than reusing crushed originals.
| Brand | Purex (Pentair) |
|---|---|
| Manufacturer part number | 72172Z |
| Type | Split lock washer |
| Material | Stainless steel |
| Size | 1/4" |
| Quantity required | 2 |
| Fits | Purex CFW cartridge filters CFW 120, 180, 315, 405; Purex 4000 Series molded DE filters SM/SMBW 4024, 4036, 4048; Pentair SM and SMBW 2000 Series backwash valves; Pentair EQ Series commercial pumps |
| Shipping weight | 0.05 lb |
| Ships | Parcel |
Request a quote
Need a volume price, a freight quote, or pricing in writing before you order? We reply the same business day.
Customer reviews
More from Pentair
Questions and answers
What people ask about this product, answered by our pool techs.





















