When troubleshooting your priming issues, there are 5 main areas you should check to help you find the source of the issue. The inlet strainer, suction hose, inlet ball, pump, and prime valve should all be examined for defects which may affect the priming capabilities of the sprayer. In the video, Greg gives a thorough run-through of each of the key areas and what issues may be affecting each part. 


Inlet strainer

The first part of the sprayer you should check is the inlet strainer. If the inlet strainer is blocked, it will greatly reduce the pump’s ability to prime. The pump relies on air pressure alone to push out the paint, so it’s important to make sure nothing is stopping the paint from being released.


Suction hose 

Next, examine the suction hose for damage or air leaks. Air leaks on the suction hose can also affect the pump’s ability to prime. A handy tip is to use plastic wrap around the flanges or suspected areas to test for ingress leaks. 


Inlet ball 

The inlet ball and seat need to act together to seal and stop the paint from running back out of the suction tube when the pump piston goes down. If the ball and seat are obstructed by foreign matter or worn to the point where the seal no longer works, the paint will run back up. 


Priming issues may be a result of an issue with the pump itself. You can determine if the pump requires servicing by checking if it holds pressure under load. If the pump doesn’t hold pressure, it may require its packings to be replaced. 


Prime valve 

Although it only happens on rare occasions, there may be an issue with the prime valve (which switches the sprayer from the prime setting to the spray setting). Sometimes blockages may occur in the prime valve. If you have checked all the other areas and you feel as though there may be an issue with the prime valve, you can remove the prime valve with a spanner to inspect it. By giving the valve a thorough clean, you may be able to fix the issue. 


We would also like to say a big thank you to Greg from Graco for coming out to PaintAccess to help with the demonstration! We are very grateful that he was able to take time out of his day to give us a hand. We hope that this video helped you to know how to detect priming issues in your pump. If you have any further questions or concerns, please feel free to reach out to us via phone and one of our representatives will be in touch to provide expert advice.