Product Overview
The original-style pressure relief valve for Hydro-Force pump-up sprayers. It vents tank pressure — both as the safety device while you work and as the means of depressurising the tank before you open it.
It will replace a damaged pressure relief valve on the AS16, AS18, AS202 and AS204 sprayers of the older generation.
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 valve body is polypropylene. The Chapin cross-reference is 6-4645, which is worth quoting if you are checking availability elsewhere.
The relief pressure is not published by the manufacturer. We have looked across Chapin's own listings, the distribution catalogues and the Interlink parts documentation and no figure is stated anywhere. We would rather tell you that than print a number we cannot stand behind. If you need the setting for a compliance or risk assessment, contact us and we will request it from the supplier.
Correction: an earlier version of this page stated that this valve mounts in the tank lid. That was not correct for the old-style sprayer — lid mounting is the identifying feature of the new generation. The page has been corrected.
Specifications
| CCW SKU | NA1610 |
| Type | Pressure relief valve |
| Generation | Original / old style |
| Body material | Polypropylene |
| Fits | Old-generation AS16, AS18, AS202, AS204 |
| New-style equivalent | NA2310 — does not interchange |
| Chapin cross reference | 6-4645 |
| Relief pressure | 40 to 60 psi. Confirmed by CCW; not published by Chapin |
Frequently Asked Questions
Can I run the sprayer without a working relief valve?
No. It is the pressure safety device on a vessel you pump by hand, and it is how you depressurise the tank safely before opening it. A seized or removed relief valve is an injury risk, not an inconvenience.
How do I know which one I need?
Look at where your existing valve sits. On the pump assembly means old style and this part. On the tank lid means new style and NA2310.
Why has mine failed?
Most failures here are chemical rather than mechanical — the valve sits in the vapour space above whatever is in the tank. Sprayers left loaded between jobs are much harder on it than sprayers emptied and rinsed.
Does the new-style valve fit an old-style sprayer?
No. Chapin states the old valve is not compatible with the XP generation, and the reverse does not hold either. Match the valve to the sprayer.
Related Products
- Pressure Relief Valve NA2310 (new style)
- TWBS Pump Assembly (NA1616)
- Hydro-Force TWBS Sprayer 8 Ltr (AS202)
- Hydro-Force TCBS Sprayer 12 Ltr (AS16A)
- Brass Shut Off Valve for TWBS Sprayers (NA1608)
What We See in the Field
"It keeps hissing out of the relief valve." If a pressure relief valve is venting, treat that as information instead of defeating the valve. When the valve no longer holds or releases consistently, replace it with the correct part for that sprayer.
Not sure which generation you have? Send us a photo of the lid and pump — it takes a minute and saves a return.
