The sealing disk inside the valve. When the gun drips with the trigger released, this is almost always the part that has failed.
Fitment
- Spraying Systems Series 31 valves
- Metal spray guns using the NA0820 body
Important: Check Which Valve You Have
US distributors list NA0822 as the shut-off disk for the NA0820 metal gun (Spraying Systems GunJet model AA23H, as used on older Hydro-Force AS08 injection sprayers). Spraying Systems' own parts lists for the Series 31 (AA31) valve show a different sealing part — a brass and PTFE seat, CP7490. We have kept CCW's Series 31 listing but cannot confirm from published data that this disk fits the Series 31. If yours is a Series 31 valve, send us a photo before ordering.
Specifications
| Part | Shut-off disk |
|---|---|
| Suits | Metal GunJet NA0820 (Spraying Systems AA23H); Series 31 valve as listed by CCW — see above |
| Material | Not published |
| CCW SKU | NA0822 |
Diagnose Before You Order
A gun that will not shut off cleanly has one of three problems: the disk has hardened, split or picked up grit; the seat it closes against is scored; or the nut holding the assembly has worked loose. The disk is the cheapest and by far the most common, so start there.
If a new disk does not fix it, the lock nut and brass nut are the next parts in the same assembly. On the NA0820 gun, the NA0821 repair kit covers the stem and seals.
Filter Your Solution
Disks that fail early are almost always failing because of grit. If you are replacing them often, the problem is upstream — check the solution filter and the tank.
Fitting
- Release all pressure from the sprayer and point the gun into a bucket.
- Strip the valve, noting the order of parts — a photo on your phone saves guesswork.
- Clean the seat and check it for scoring before fitting the new disk.
- Reassemble, pressurise with water and check the gun shuts off cleanly before going back to chemical.
Frequently Asked Questions
My gun still drips with a new disk. What next?
Check the seat for scoring and the nuts for tightness. If the stem or packings are worn, the NA0821 repair kit is the next step on the NA0820 gun.
What is the disk made of?
The material is not published by our supplier. If you are spraying solvents, tell us the chemical and we will check compatibility before you order.
Related Parts
Tell us the gun or valve you are repairing and we will confirm the part before you order.
