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Troubleshooting Graco Airless Paint Sprayer: How to Fix Common Problems

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Matt is a professional painter who owns and operates his own painting business, specializing in interior and exterior house painting.

My Graco GX-19 Finish Pro airless sprayer

My Graco GX-19 Finish Pro airless sprayer

Common Airless Sprayer Problems and How to Fix Them

Nothing is more annoying than running into unexpected problems with your paint sprayer in the middle of a project. Unless you have a local shop in your area who does airless sprayer repair work, you are often forced to fix the problem yourself, or send it in for repair through a paint store, which can take weeks.

Whether it's a Graco sprayer, Titan, or another brand, all paint sprayers will have issues at some point, but sometimes the issues are the result of improper set up, and other times it's worn parts.

I own three different paint sprayers from Graco. I own the 495 Ultra Max, the GX-19 Finish Pro and the 9.5 Pro Comp HVLP sprayer. All three of my sprayers, especially my oldest, the Ultra Max, have been very reliable to me over the years with only a few minor issues. I always clean my sprayers after every use and store them properly. Carefully cleaning Graco sprayer parts is critical to avoiding a host of problems.

On occasion, I run into problems while spraying with my Graco sprayer. I'll go over some problems you might be experiencing so you can troubleshoot and fix your Graco airless sprayer. These common problems and fixes can be used for any sprayer brand, not only Graco.

1. Airless Spray Gun Spitting

Almost every airless spray gun I've used spits droplets of paint upon trigger release, and this worsens when using a spray gun extension. Spitting can become a problem when it comes to fine finish painting for cabinets and doors. The simple solution is to get into the habit of releasing the trigger beyond the substrate you're spraying, not over the top of it. But if your Graco spray gun is spitting really bad, there could be one or more reasons for that.

Reasons your spray gun is spitting badly:

  • Material build-up on the tip guard
  • Air inside the fluid hose and pump
  • Dirty and worn spray gun assembly
  • Pressure too low

What to do:

Check your pressure. First make sure the pressure isn't set too low for the material you're spraying. If the pressure is too low, the material you're spraying won't fully atomize, especially if you're spraying something really thick. I would also try using a spray tip with a larger orifice. If you're getting a combination of spitting and a broken spray pattern, the problem is likely the spray tip size.

Prime the pump. Your Graco sprayer should have been primed too during set up to remove air from the pump and hose. Without priming, air gets trapped inside the pump and hose and leads to spitting. If you did not prime the pump, disengage the pressure and cycle through some paint to purge the air. Always do this before spraying.

Check the tip guard. Another common cause for a spray gun spitting is blockage caused by paint build-up on the tip guard. If you don't keep the tip guard clean, sometimes wet paint will collect right outside the opening of the spray tip, and when you pull the trigger, the accumulated paint gets blasted onto what you're spraying.

Clean the fluid needle. If you've tried everything else without any luck, disassemble the gun and check the fluid needle. Certain coatings, especially solvent-based coatings, are sticky and can build up around the needle and cause problems. Try cleaning the needle and the inside of the gun. If the problem persists then the packing's and parts are likely worn and need to be replaced, however, these are easy to replace yourself with the Graco gun repair kit. Choose the kit built for your particular Graco gun.

The Graco Contractor spray gun.

The Graco Contractor spray gun.

2. The Sprayer Won't Prime and Pressurize

This is one of the most annoying problems you'll experience on occasion with airless sprayers in general, not only a Graco. You turn the sprayer on and try to prime the pump, but the sprayer won't prime at all, or even pressurize, when switched back to spray mode. Sometimes when this happens the piston will pump up and down constantly regardless of what mode you're in. It's frustrating, but sometimes it's a really easy fix.

Reasons your sprayer isn't priming, or building pressure:

  • The ball check is obstructed and not seated properly
  • Clogged siphon hose
  • Bad transducer

What to do:

Inspect the ball check. In the fluid section of your Graco sprayer, depending on your model, there is one or more ball checks, or ball seats. The ball must be seated properly for a tight seal so the pump can build pressure. In my Graco GX-19, a dead fly made its way into the fluid section and obstructed the ball, so the sprayer would not pressurize. Once I discovered the dead fly and removed it, the problem was resolved. Paint can also collect on the ball and cause problems when it sticks. On my Graco 495 Ultra Max, I can remove the ball and clean it if it's dirty.

Check the siphon hose. The siphon hose is the intake that siphons your paint up from the can, or bucket, into the pump. The pump can't pressurize if it's unable to cycle paint up into the pump. Over time, paint can build up inside the hose and clog the inside if you don't keep it clean. Unscrew the rock catcher (metal strainer) on the end of the siphon hose and make sure there are no obstructions inside.

Replace the pressure transducer. If your pump is running, but simply won't prime, or pressurize, the transducer is likely fine, but if the pump isn't running at all, the transducer might be toast and in need of replacement. The transducer tells the pump that pressure is needed, and without it, your sprayer won't work. So far, I haven't had to replace the transducers on any of my Graco sprayers.

3. Paint Leaks From the Spray Tip Housing

Paint leaking from the spray tip housing can become a messy problem really fast until you find the source of the problem. Sometimes you won't notice the paint leaking until it worsens and starts dripping from the housing. This problem is usually isolated to the spray gun.

Reasons your spray gun is leaking paint:

  • Improper seal from dirty threads
  • Worn gaskets

What to do:

Clean the threading on your spray gun. The first time this happened to me I had no idea what was causing the paint to leak out of my Graco tip guard until I realized the threads on both the spray gun and the tip guard itself were dirty. The threads accumulate paint over time and prevents the tip guard from screwing on correctly to form a tight seal. Without a proper seal, paint will definitely leak out and make a mess. Remove all of the dried paint from the thread. I used paint stripper to clean mine and solve the problem.

Replace the gasket. The rubber gasket inside the tip guard degrades over time, especially when paint thinner, or lacquer thinner, are used for cleaning the sprayer. Check the gasket to see if it's cracked, or not seated properly. If it's loose, push it back in with your finger. Like the threads on your tip guard and spray gun, if the gasket isn't making a proper seal, paint is sure to leak out. Replace the gasket if it's damaged.

This content is accurate and true to the best of the author’s knowledge and is not meant to substitute for formal and individualized advice from a qualified professional.

© 2021 Matt G.