Robust Single Air Release Valve Air Vacuum Valve Easy Maintenance

Working Pressure:16kg/cm²
Shell Test Pressure:24kg/cm²
Seat Test Pressure:18kg/cm² 
Media:Water,Neutral Oil
Working Temperature:0-52°C

100％ Fusion Bonded Epoxy Coating for Inner and Outside Surface 
Size:DN25

A DN25 Air Valve That Survives the Field — and Repairs in Place

DN25 air valves live hard lives. They are installed at the furthest end of branch lines where sediment collects. They sit on pump casings next to vibrating machinery. They thread into filter housings that are backwashed daily. They are the most numerous, most dispersed, and least-visited air release devices in any water network — and when one fails, it can take weeks before anyone notices the reduced flow, the increased pump amps, or the air-bound pipe section. The Model 4001S Robust Single Air Release Valve is engineered for this reality. It is a DN25 threaded, PN16 rated, ductile iron air release valve designed with two overriding priorities: robustness — to keep functioning in the dirtiest, most demanding installations without failure — and easy maintenance — to be inspectable, cleanable, and repairable in the field by a single operator with basic hand tools, without removing the valve from the pipe. It is the DN25 air valve you specify for pump stations, well fields, remote manifolds, and anywhere a stuck float means a long drive to fix.

Product Overview

The Model 4001S is a single air release valve, DN25 threaded, PN16 rated, for water and neutral oil service. It employs a single float-operated orifice that automatically vents air at system operating pressure. The float is a solid-welded stainless steel 304 sphere — corrosion-proof, permanently buoyant, incapable of water-logging. The body is cast from EN-GJS-500-7 (GGG50) ductile iron with 100% internal and external fusion bonded epoxy coating (250 um DFT, spark-tested at 3 kV). Key to the 4001S's "easy maintenance" design is its serviceable bolted cover — the top cover can be removed on-site using standard spanners, giving direct access to the float, guide mechanism, orifice, and seal. No special tools, no cutting, no heating, no hoist. The float assembly lifts out for cleaning, the orifice seat can be wiped and inspected, the seal can be replaced if worn — all without disturbing the pipe connection. This is not a disposable valve — it is a maintainable asset. Manufactured by Shandong Huaze Valve Co., Ltd. (ISO 9001, since 1998), every 4001S is shell-tested at 24 bar, seat-tested at 18 bar, and verified for float operation before dispatch.