During last Friday's stock check, a long-standing water treatment customer called: two gate valves stocked last year, with the project only confirmed this year — can they be shipped over and installed as they are? We told him to hold on. A valve at factory acceptance is one thing; the same valve after more than half a year in a spares storeroom is quite another.
We've encountered this several times in recent years. A spares storeroom is not a safe deposit box — valves left untouched in storage reveal their problems only once installed on the line, when the schedule is even tighter.
In Long Storage, Stems and Packing Go First
When a valve sits still for a long time, the rust-preventive oil on the exposed stem gradually dries out. In a more humid warehouse, rust spots can appear on the stem within six months. Packing is another easily overlooked item: flexible graphite packing loses some of its compression resilience over time, and the handwheel will feel noticeably stiff when the valve is stroked again.
Gate and globe valve stems are moving parts for full open/close; in ball and butterfly valves left idle for long periods, the grease between the sealing pair also hardens. None of these problems show from the outside — they surface only after installation.
Stroking Before Installation Is the Cheapest Maintenance Step There Is
Our advice to customers is simple: any valve untouched for more than three months must be stroked before installation. Gate and globe valves from fully closed to fully open and back; ball and butterfly valves turned 90 degrees. Only if the motion is smooth, without sticking or unusual noise, should the valve move on.
Valves that won't stroke come up often on real projects — usually packing compressed too tight plus slight stem corrosion. Add a little lubricating oil, loosen the gland half a turn, and try again. Hammering the handwheel only bends the stem, and then the valve really is scrap.
Sealing Faces and Flange Faces: Inspect, Wipe, Protect
After stroking, inspect the sealing faces. Check the disc and seats for rust spots and dents, and after closing, for visible light transmission; check the flange sealing faces for scratches and whether the protection caps are still in place. Remove any rust spots with an oilstone in one direction, then apply a thin coat of rust-preventive oil.
We also recommend re-checking the shipping documents while you're at it: whether the certificate and inspection report match the model, pressure rating, and material on the nameplate. When projects get busy, mixing up valve spares in the storeroom is not rare — install the wrong pressure rating and it won't survive the pressure test.
Manage Valve Spares: FIFO and Regular Stock Rotation
Spares management isn't the storekeeper's job alone. Register valves into stock with a date, shelf them by specification, rotate first-in-first-out, cycle the stock quarterly and stroke every valve while you're at it — far easier than emergency repairs after a failure. One extra line in the ledger for the stocking date means one more measure of confidence at issue. In northern warehouses where winter condensation is a problem, a few packs of desiccant in the packaging cost little and help a lot.
If your spares storeroom also holds valves that have been sitting for a while, or you're unsure whether a particular valve can be installed as is, send us a photo of its nameplate and we'll assess it against SUFA's actual product condition. For selection needs on new projects, browse the relevant series in the product center or contact us directly.
Suzhou Akameng Automation Equipment Co., Ltd. · Officially Authorized SUFA Distributor (Authorization No. SFSQ-0036) · Tel 0512-66673578 (WeChat 15851489497)