Graco Airless Paint Sprayer — Troubleshooting Guide: Causes, Tests & Fixes

Before you troubleshoot, shut down the sprayer and depressurize the system following the manufacturer instructions. Disconnect power and relieve any stored pressure in the hose and pump area. Put on appropriate PPE, including eye protection and gloves, and secure the work area from bystanders.

Set up your prep area with clean rags and a bucket for test material. Verify you have the correct nozzle, tip, and filters for your job and confirm any safety warnings in the label or data sheet. If unsure, check the manufacturer instructions or local rules before proceeding.

Safety and prep

Before you start troubleshooting, ensure your safety and the sprayer’s. Use this checklist.

Start with a visual check of the entire system for obvious restrictions, kinks, or leaks. Run a simple test by triggering the gun with no material to see if it sprays evenly and consistently.

Next, swap the tip and inspect the hose for damage, then test again. If the issue persists, test the pump with the material at a reduced setting or a different can to determine if the problem is tip, hose, pump, or material related.

Prime and suction tests

Before you start, make sure your sprayer is unplugged. Grab a bucket of paint and place it on the ground near your sprayer.

First, prime your sprayer. This means filling the pump with material so there are no air pockets. Pour some paint into the inlet, then open the valve to let gravity do its work. Close the valve once paint starts coming out of the outlet.

Next, check the suction path. Connect your hose and tip, then submerge the intake in your paint bucket. Open the suction valve. If paint flows freely, your suction path is clear. If not, you might have a blockage or leak.

Pressure and flow checks

Plug in your sprayer and turn it on. Check the pressure gauge on the pump. It should read within the range specified by Graco (usually around 1000-2500 PSI). If it’s too low or not working, there might be an issue with your pump.

Now, check the flow at the gun. With the trigger pulled, paint should come out consistently and evenly. If it’s weak or inconsistent, you could have a blockage in the hose or tip, or a problem with the pump.

To test further, close the spray gun valve and open the bleed valve on the pump. Paint should come out steadily. If it doesn’t, or if there’s air coming out, you might have an issue with your pump or hose.

Back to top ↑

Check the tip and gun openings for obstructions and clear any debris with the appropriate tool. Inspect inline filters and the suction strainer for buildup that could restrict flow.

Run a purge to determine if flow improves after removing blockages. If the system still shows reduced flow, verify the filter specifications and installation per the product label or manufacturer instructions before proceeding.

How to detect a clog

A sudden loss of spray pattern or just a tiny pinhole of paint coming out could mean you’ve got a clog somewhere. Here’s how to find it:

First, shut off the power and turn the spray gun upside down. If paint drips out, your tip might be clogged.

Next, check the inline filter. If it’s full of paint or debris, that could be your culprit.

If neither of those are the issue, there might be a blockage in the gun or hose. You’ll need to do some more digging to find it.

Cleaning and unclogging procedures

When you’ve found the clog, it’s time to clean it out. Here’s how:

For tips, use a tip cleaner brush or a wire to gently poke through the opening. You can use water or cleaning fluid, but be sure to follow the manufacturer’s instructions.

To clean the inline filter, remove it and tap out any dried paint. Rinse it with water and let it dry before putting it back in.

For hoses and guns, use a flush kit to push cleaning fluid or water through the system. This will help dislodge any clogs. Again, follow the manufacturer’s instructions for the best results.

Back to top ↑

Uneven spray often comes from changes in distance, angle, or fan width. Check for a consistent fan shape and adjust the nozzle height and spray angle as needed. Look for splatter or fishtailing as a sign of instability in setup.

Verify that the material is at the recommended viscosity and that the tip size matches the job. Inspect seals and the gun body for wear that could affect spray consistency, and consult the instructions if adjustments are required.

Tip selection and wear

The right tip makes all the difference. Inspect your current one for wear. A worn tip can cause fishtailing or streaks.

Check for: rounded edges, uneven surfaces, or signs of damage. If you see any, it’s time to replace.

Choose a tip based on your material and desired fan size. The Graco manual has charts for this. A too-small tip can cause splattering, while a too-large one leads to poor coverage.

Material thinning and viscosity checks

The paint’s thickness affects the spray pattern. Too thick, it won’t atomize properly. Too thin, it’ll mist and cause overspray.

• Check your material’s viscosity: It should be like heavy cream at room temp. If it’s too thick, thin it according to the manufacturer’s guidelines.
• Use a 50/50 mix for water-based paints: This is a good starting point. Adjust as needed based on your results.
• Avoid thinning oil-based paints too much: They can become too fluid and lose their adhesion properties.
• Check your material’s rating: Some materials are designed for specific sprayers. Use the right one for your Graco.
• Avoid using materials with high solids content: These can clog your tip and cause poor coverage.

Back to top ↑

Inspect all fluid connections for leaks or loose fittings that could cause pressure changes. Listen for abnormal pulsing or spitting at the gun, which can indicate air leaks or viscosity issues.

Test with clean material and confirm the pump is cycling smoothly. If pressure instability continues, verify settings against the label or data sheet and check for worn packings or seals as part of the next steps.

Hose, Fittings and Leaks

Pressure loss, pulsing, or spitting at the gun can be due to leaks in your Graco airless paint sprayer’s hose system. Here’s how to check:

Visual Inspection: Look for any visible cracks, holes, or bulges along the length of the hose.

Pressure Isolation Test: Disconnect the hose from the gun and the pump. Place your hand over the end of the hose near the gun. If you feel air escaping, there’s a leak between that point and the pump. Repeat this test on the other side to pinpoint the exact location.

Loose fittings can also cause pressure issues. Tighten them up if they’re not secure.

Pump Intake and Packing Issues

The pump’s intake valves, check valves, or packings can wear out over time, causing pressure problems. Here’s how to identify these issues:

Loss of Prime: If your sprayer won’t prime or loses its prime quickly, it could be due to worn intake valves or check valves not sealing properly.

Pulsing: If you’re experiencing pulsing at the gun, it might be due to worn packings around the pump’s pistons. This causes inconsistent pressure as the sprayer cycles.

If you suspect any of these issues, it’s time for a pump servicing. Disassemble and inspect the components, replacing them if necessary.

Back to top ↑

Trace external leaks to their source, starting at connections, hose fittings, and the gun collar. Look for drips around seals or the pump housing that indicate wear or damage.

For internal seals, consult replacement guidance and safety procedures. If unsure, verify part numbers and warranty guidelines from the manufacturer or authorized service instructions before attempting fixes.

Visual checkpoints for seals and O-rings

Before you start, grab a flashlight. This checklist helps find worn-out seals and O-rings.