Product Overview
Check valve repair kit for Hydro-Force injection sprayers. It rebuilds the check valve in the chemical draw circuit — the assembly that lets the sprayer pull concentrate in and stops it running back out.
What Is in the Kit
One of each of the following:
| Part | Item |
|---|---|
| NA0837 | O-ring cap seal |
| NA0810 | Check spring |
| NA0811 | Steel ball |
| NA0838 | Cap liner |
| NA0813 | Nylon spacer for check valve |
| NA0814 | O-ring for check valve |
These items are not sold separately. If any one of them has failed, the kit is the only way to get it.
When the Check Valve Is the Problem
A failing check valve on an injection sprayer shows up as a dilution fault rather than a leak. The symptoms:
- The sprayer draws weakly or inconsistently
- Concentrate siphons back into the container when the trigger is released
- The mix is weaker than the metering tip should be giving
- Draw stops altogether while water still sprays normally
Before condemning the valve, check the strainer and confirm your working pressure — both produce the same complaint. Higher line pressure draws proportionally less chemical, which reads as a weak mix. See Metering Tip Kit (NA0816A) for how pressure moves the ratio.
Specifications
| Part number | NA0841 |
|---|---|
| Type | Check valve repair kit |
| Fits | Hydro-Force injection sprayers |
| Contents | Six items, one of each — see the table above |
Operating Advice
- Lay the parts out in order as they come off. A check valve goes back one way.
- Replace everything in the kit, not just the failed item. The rest are the same age and have seen the same chemistry.
- Work clean. A steel ball and seat will not seal against grit.
- Flush the sprayer after solvent-bearing chemistry. Most check valve failures start as seal swelling from what was left sitting in it.
Frequently Asked Questions
Can I buy just the spring or just the ball?
No. These items are not sold separately — the kit is the only way to obtain them.
My sprayer draws weakly — is it definitely the check valve?
Not necessarily. Check the strainer and your working pressure first; both cause the same symptom and neither needs a rebuild.
Does it fit the low pressure sprayer as well?
Tell us which sprayer you have and we will confirm before you order.
Is this the same as the injector valve assembly?
No. The complete assembly is a separate, much larger part. This kit rebuilds the check valve within the draw circuit.
Related Products
- Chemical Draw Tube (NA0817)
- Metering Tip Kit HP (NA0816A)
- Mesh Strainer without Check Valve (NA0803)
- Injector Valve Complete Assembly (NA0809A)
What We See in the Field
Dilution complaints on injection sprayers are diagnosed in the wrong order more often than not. Pressure first, then the strainer, then the check valve — the cheapest checks are also the most likely causes, and a rebuild kit fitted to a sprayer running at the wrong pressure changes nothing.
