If your Versa is struggling to prime there are a number of factors that can contribute to this. Obviously, the Versa is a very capable dosing pump, and taking the actions below will ensure you do not have any priming issues.
Container Volume: This is the simplest and most common issue to troubleshoot. Ensuring your dosing container is adequately filled sounds trivial but happens more often then you think. We recommend entering your container volume into the Mobius app to help keep track of container volume.
Head Pressure: Limiting your head pressure on the suction side of your Versa will eliminate most priming issues. In other words, using as little tubing as possible and limiting your vertical lift. It's important to remember the Versa can push fluids three times further then it can pull!
Air Leaks: Air intrusion into your tubing will prevent the Versa from priming. Making straight and clean cuts into your tubing are critical. Then ensure you've fully inserted your tubing into any connectors. For best results, we recommend using RODI tubing and a sharp cutting tool.
Dose Rate: Slow and steady wins the race when it comes to dosing. When encountering a priming issue we recommend lowering your dose rate to under 20ml per minute. At low speeds, your Versa generates much more torque thus creating more suction.
Internal Tubing: A misalignment can sometimes occur on the internal tubing. To troubleshoot, press the internal motor tubing using your fingers so that it's being compressed by each of the 3 motor rollers.
Blockage: Should your Versa be unable to prime at all, you may have a blockage. We recommend checking all connections and cleaning or replacing your tubing in the case of severe blockages. Blockages are not common but worth investigating assuming you've attempted all other troubleshooting steps.