How to load a cartridge and reset the piston
Every ShotLog pen takes a standard 3 mL glass cartridge. Changing one is the same on the V2 pens, Original Style or New Style: pull the cap, take the cartridge holder off (unscrew it, or on the New Style twist it and pull it off), take out the old cartridge, push the piston rod back into the pen, drop the new cartridge in, and put the holder back on (screw it on, or on the New Style push it on and twist to lock). Then prime the pen: turn the dose knob to 50 or 60 and press the button until the piston rod meets the cartridge stopper; you may need to do that a few times. Priming is the step most people skip, and it is the reason a new pen seems to deliver nothing on the first press.
The piston rod is the black rod inside the pen body. Resetting it means pushing it straight back into the pen by hand, with the holder off, so a full cartridge fits; a new pen already sits fully back. Once the cartridge is in, each press of the button moves the rod forward a fixed distance. Liquid only starts to move once the rod is touching the rubber stopper at the bottom of the cartridge, which is why you bring it up to the stopper first. That is what priming means on these pens. The priming guide goes into it in more detail, and covers clearing the air from a new needle before the first dose.
How to load a new cartridge
- Pull pen cap off to reveal the cartridge holder.
- Take the cartridge holder off: unscrew it (Original Style, 510(k) and Auto Pen), or on the V2 New Style twist it and pull it off. Take out the old cartridge, if there is one.
- Reset the piston: push the black piston rod straight back into the pen body by hand until it stops. A new pen already sits fully back.
- Drop the filled cartridge in. Put the holder back on: screw it on, or on the New Style push it on and twist to lock.
- Prime the pen: turn the dose knob to 50 or 60 and press the button until the piston rod meets the cartridge stopper. You may need to repeat this a few times. Do NOT force it: stop pressing once the piston sits gently against the stopper.
What you need
- A ShotLog pen (V2 Original Style, V2 New Style, 510(k) 80 unit pen or Auto Pen).
- A filled 3 mL glass cartridge. Filling is covered in the transfer and vent needle guide.
- An alcohol pad for the rubber stopper and a new pen needle, for clearing the air once the pen is primed.
If the piston will not move
The piston is spring-loaded, so a cartridge must be installed. Prime the pen: turn the dose knob to 50 or 60 and press the button until the piston rod meets the cartridge stopper. You may need to repeat this a few times.
On the V2 Original Style, if the holder seems to be missing: On the V2 Original Style, the cartridge holder is part of the pen body and sits under the cap. To access the cartridge holder, the pen must be screwed together, then simply PULL the cap off (do not unscrew).
Swapping a partly used cartridge
Take the holder off, lift the cartridge out and keep it safe in a Cartridge Vault or the ReconStation Cartridge Holder. Before it goes back in, or into another pen, the piston rod may need to be pushed back down into the pen so the cartridge fits. Then prime the pen again with the same routine: knob to 50 or 60, press the button until the piston rod meets the stopper, repeat if needed. The piston does not remember where it was. A cartridge that has been used up is single use: discard it and load a fresh one rather than refilling it.
On the Auto Pen
The Auto Pen loads the same way: its cartridge holder screws on, like the Original Style and 510(k) holders. The steps are on its product page.
After the cartridge is in
With the pen primed, clear the air from a new pen tip before the first dose: the priming guide covers that step and what the bead of liquid tells you. If the pen still delivers less than the dial shows after that, the troubleshooting guide lists the causes in the order we see them. Questions go to [email protected].
Watch the piston reset video on the how-to videos page.
Products in this guide
Related guides
For research use only. Not for human or animal therapeutic, clinical, or diagnostic use. Not FDA-approved.
