Airless Paint Sprayer Won’t Prime or Build Pressure

Airless sprayers are often the backbone of your painting work, especially for handling large volumes of painting quickly and efficiently. There are a variety of common problems that you can encounter with an airless paint sprayer which are laid out here. Another problem that can often occur with an airless paint sprayer is that material won’t spray when the sprayer is turned to the spray cycle, but it will typically spray if the pump is placed in dump mode. If this is the issue that you are having with your airless paint sprayer the following tips will help you decided which of the two issues your having and how to properly fix them.

First Airless Paint Sprayer Test – Do you hear the pump trying to run

The first question is whether you hear the pump running when you turn it on.  If the pump is not trying to run that would suggest that it is falsely determining that pressure is already appropriate in the pump, which is obviously not accurate as the pump has no pressure built up. If this is the issue you experience the most likely cause is that the transducer is worn out. The transducer signals to the airless pump that pressure is needed and signals to run the pump to build pressure. Failure to build pressure often indicates that you need to replace the transducer.

Second Test – Does the Airless Pump Not Primer or Build Pressure But the motor is Running

If the pump is running but material is not being supplied there are a few things to check for. First, check the upper and lower ball and seats of the airless pump.  The ball and seats close opposite of each other allowing the material to be forced out of the airless pump and allowing you to spray.  If there is material built up on either ball or if the ball and seat are worn it may prevent the ball and seat from creating a firm stop which will prevent pressure from being able to be built up. When you remove the ball and seat clean them properly and then you can set the ball against the seat and try to blow air around the ball while it sits against the seat. If you can blow air past the ball when it is seated the ball or seat are worn. You may also notice a ball and seat are worn if you find that pressure is ok on one part of the airless piston stroke but not on the other this would suggest the ball and seat on one end of your airless piston are worn or dirty preventing a tight seal.

If the ball and seats on your airless sprayer are in good condition you should also check the siphon hose. If the siphon hose has a hole in it or is not tightly secured to the airless sprayer the system may not be sealed and as a result, may suck air in while trying to pick up material. This can lead to the system not pressurizing well. You will usually be able to tell if this is happening because you will hear the pump running rapidly but pressure will not build well.

Knowing what can cause an airless paint sprayer to not prime or build pressure can be critical as it can help you figure out how to fix your airless sprayer and get back to painting.  If you have issues with your sprayer and want assistance we offer airless paint sprayer repairs.