How to prevent your Injector from Sticking
If the injector or ‘plunger’ is not returning smoothly after a dose is delivered it can quickly get frustrating.
This can happen if:
- The O-ring on the plunger that cycles inside the fluid junction is dry and not lubricated
- Operating in dusty/dirty conditions. Grit has has found its way into the dual stage injector internal workings
- The needle is bent and dragging against the metal housing
- The device has been left uncleaned in a dusty shed all year and needs a very quick bit of TLC before lamb marking begins
The stiction or ‘snatchy’ feeling normally results in the user pulling back on the orange button to withdraw the needle and draw up the next dose.
After multiple cycles, the additional force of the human pull as well as the spring can eventually cause the dual stage injector orange button to fall off, and the spring will pop out.
This seem like a dramatic failure, yet if it happens to you, there is a quick farm fix below.
To prevent this keep your injector in prime condition by keeping it lubricated.
- Keep the O-ring lubricated with olive or sunflower oil, only ever use organic based oil.
- Spray a dry silicon lubricant (like RP7) on the injection parts and channels (photo to the right)
Using a dry teflon/silicone is preferable over grease or oil as it is less likely to pick up dirt and dust if the device is dropped.
Has the orange button has come off?
Here is a quick farm fix...
- Replace the counter sunk bolt and brass insert with a 25-35mm wood screw. All dual stage injectors from July 2021 onwards fix the orange button in with a longer self tapping screw.
- If you don’t have a screw handy you can glue the brass insert back into the plunger with epoxy or superglue, and the screw and cap together with super glue.
- Dual stage injectors should last tens of thousands of doses if they are cleaned and lubricated. The modular nature of the Numnuts system means the injector can also be replaced with a spare by removing the two alan screws underneath with a 2.5mm hex key.
A spare dual stage injector can be purchased here:
