Product Overview
The new-style pressure relief valve for Hydro-Force pump-up sprayers, with fluoroelastomer (Viton) seals. It mounts on the tank lid and is lockable open or closed.
It replaces the pressure relief valve on the current-generation AS18, AS202 and AS204.
Which Generation Is Your Sprayer?
The AS18, AS202 and AS204 changed generation, and the parts are not interchangeable. There is a look-and-see test that needs no serial number and no tools.
- Relief valve on the pump assembly — you have the old generation. It takes Pressure Relief Valve NA1610 (old style).
- Relief valve on the tank lid, lockable open or closed, usually alongside a moulded wand clip on the lid — you have the new generation. It takes Pressure Relief Valve NA2310 (new style).
These sprayers are built by Chapin and badged Hydro-Force, and the change tracks Chapin's move to its XP series. Chapin states the older valve is not compatible with XP sprayers, so this is the manufacturer's own position rather than our inference.
If you are not certain, send us a photo of the lid and pump before ordering.
Technical Notes
The Chapin cross-reference is 6-4605 — Chapin item number 988134, the XP-series relief valve. Quoting that number is the quickest way to check availability if you are ever stuck.
The seals are fluoroelastomer (FKM / Viton), which is the substantive upgrade over the old-generation valve. Viton holds up to solvent-bearing chemistry that would swell and soften a nitrile seal.
Two things we cannot tell you. The relief pressure is not published by Chapin or any distributor. And Chapin makes a closely related acid-service variant (6-4606); we have not been able to confirm from documentation which of the two this part is. If you are running acid rinses through the sprayer, contact us and we will confirm with the supplier before you order.
Specifications
| CCW SKU | NA2310 |
| Type | Pressure relief valve, tank lid mount, lockable |
| Generation | New style / Chapin XP |
| Seal material | Fluoroelastomer (FKM / Viton) |
| Fits | New-generation AS18, AS202, AS204 |
| Old-style equivalent | NA1610 — does not interchange |
| Chapin cross reference | 6-4605 (item 988134) |
| Relief pressure | 40 to 60 psi. Confirmed by CCW; not published by Chapin |
| Acid-service variant | Chapin 6-4606 is a separate part. This is the standard 6-4605, not the acid-service valve |
Frequently Asked Questions
How do I know I need the new valve, not the old one?
If the relief valve sits on the tank lid, you need this one. If it sits on the pump assembly, you need NA1610.
Is it Viton?
The seals are, yes — fluoroelastomer. That is the main difference from the old-generation valve and it matters if you run solvent-bearing chemistry.
Can I use it with an acid rinse?
Chapin lists a separate acid-service version of this valve. Until we can confirm which one we stock, we are not going to tell you it is acid-rated. Contact us first.
What pressure does it vent at?
40 to 60 psi. Chapin do not publish it; we have confirmed it through our own supply channel.
Will it fit my old sprayer if I just swap it over?
No. The generations differ beyond the valve itself.
Related Products
- Pressure Relief Valve NA1610 (old style)
- TWBS Pump Assembly (NA1616)
- Hydro-Force TWBS Sprayer 8 Ltr (AS202)
- Viton O-Ring Pump Barrel (NA1417)
- Viton Check Valve (NA2256)
What We See in the Field
If a pressure relief valve is venting, treat that as information instead of defeating the valve. First confirm the sprayer has not been over-pumped and the valve is clean and correctly seated; never plug or modify a safety relief to get 'a bit more pressure'.
Running acid through your sprayer? Talk to us before ordering — there is a variant of this valve for that and we want to send you the right one.
