Product Overview
The Viton bottom check valve for the pump barrel on Hydro-Force pump-up sprayers.
It sits at the base of the pump barrel and is what allows the pump to build pressure — it lets solution past on the down stroke and holds it there on the up stroke.
The Symptom to Look For
A failed bottom check valve gives you a pump that feels like it is working but never builds pressure, or that loses pressure as soon as you stop pumping. The handle moves freely, nothing leaks externally, and the tank simply will not come up to pressure.
That is a different symptom from a worn plunger cup, which usually feels loose or gritty on the stroke. If the pump feels normal but nothing happens, look here first.
Material
Viton, which is the right choice for a component sitting permanently in whatever chemistry is in the tank. The Chapin cross-reference is 1-4324-1.
Specifications
| CCW SKU | NA2256 |
| Type | Bottom check valve, pump barrel |
| Material | Viton |
| Fits | AS16, AS18, AS202, AS204 — listed across TCBS and TWBS parts |
| Chapin cross reference | 1-4324-1 |
| Supplied with | Included in the complete pump assembly |
| Dimensions and durometer | Not stated by the manufacturer |
Frequently Asked Questions
The pump will not build pressure. Is it this?
It is the first thing to check when the pump strokes normally but no pressure develops.
How is that different from a worn plunger cup?
A worn Pump Plunger Cup (NA2254) usually feels loose or rough on the stroke. A failed check valve feels normal and simply does not build.
Is it Viton?
Yes — stated by multiple distributors.
Should I replace the seals at the same time?
If the sprayer is apart, yes. See Viton O-Ring Pump Barrel (NA1417) and O-Ring Pump Seal AS14 & AS16 (NA1413).
Related Products
- Pump Plunger Cup (NA2254)
- Viton O-Ring Pump Barrel (NA1417)
- O-Ring Pump Seal AS14 & AS16 (NA1413)
- TWBS Pump Assembly (NA1616)
What We See in the Field
Pump seals usually fail faster when concentrated chemistry is left sitting in the sprayer between jobs. Rinsing and depressurising the unit after use does more for seal life than repeatedly rebuilding it.
Pump stroking but not building pressure? Contact us and we will help you work out which part it is.
