Verified model passport / Zurn Wilkins
375 / 375A / 375AST large-body relief valve
Reduced pressure principle assembly — large-body relief valve service
This record is intentionally limited to the large-body relief valve. Zurn publishes a different component set for 2 1/2–6 inch versus 8–10 inch assemblies, and neither should be treated as a universal 375 kit.
This is not a substitute for the 1 1/4–2 inch 375 repair path, check-service kits, valve configuration, or a diagnosis of continuous relief discharge. Confirm the exact size and repair scope before ordering.
Compatibility workstation
Match the size and repair scope.
Use the complete model label, nominal body size, and failed component. The tool only exposes combinations found in the cited manufacturer material.
Published references are listed below. Choose a size band to narrow the list.
Complete relief-valve repair kit
Published relief-valve rubber and service components including diaphragm, seal rings, relief spring, and related O-rings.
Relief-valve rubber repair kit
Published rubber service components for the relief-valve assembly.
Relief-valve complete internals kit
Upper and lower plunger, diaphragm, seals, seat, retainer, washer, bolt, and relief-valve spring in the published component matrix.
Relief-valve cover repair kit
Relief-valve cover and published cover hardware.
Relief-valve plunger repair kit
Published upper and lower plunger service components.
Complete relief-valve repair kit
Published relief-valve rubber and service components for the 8 and 10 inch size band.
Relief-valve rubber repair kit
Published rubber service components for the large 8 and 10 inch relief-valve assembly.
Relief-valve complete internals kit
Published upper and lower plunger, diaphragm, seals, seat, retainer, washer, bolt, and relief-valve spring components.
Relief-valve cover repair kit
Relief-valve cover and published cover hardware.
Identity check
Confirm this model before ordering.
Similar-looking assemblies can use different internals. A search result or pipe size alone is not enough.
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Use this record only when the assembly is a Zurn Wilkins 375-family large-body unit and the required work is specifically the relief-valve service path.
- 02
The 2 1/2–6 inch and 8–10 inch relief-valve kits have separate part-number prefixes and must not be swapped.
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A relief-valve kit is not a diagnosis: continuous discharge can involve check, pressure, debris, or installation conditions that require qualified testing.
Before return to service
A matching kit is not a passed assembly.
Stop for body damage. Cracks, distortion, severe corrosion, or freeze damage can move the job from internal service to replacement.
Test after repair. Where the assembly is regulated, the governing utility or authority decides tester approval, reporting, and deadlines.
Use the current instructions. Part references can change. Confirm availability and supersession with the manufacturer or an authorized supplier.
Find the governing utilityOfficial source ledger
Trace every compatibility claim.
No retailer copy is used as the authority for the kit map.
- 01ZurnZurn Wilkins 375 reduced pressure principle backflow preventer product recordVerified 2026-08-02
- 02ZurnZurn Wilkins Repair Kits Guide: 375 large-body relief valve, 2 1/2–10 inchVerified 2026-08-02
- 03ZurnZurn 375AR product record with repair-parts and large-body maintenance resourcesVerified 2026-08-02