Graco 390 - User Manual

Other manuals for Graco 390

Operation Manual40 pages

Repair Manual30 pages

Questions and Answers

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Christine GlennJul 30, 2025
What to do if my Graco Paint Sprayer motor won't operate?
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  aharrisJul 30, 2025
  If the Graco Paint Sprayer motor won’t operate, first, gradually increase the pressure setting to check if the motor initiates. If this doesn't work, the spray tip or fluid filter might be clogged. In that case, relieve the pressure and then clear the clog or clean the gun filter. If water or water-based paint has frozen in the sprayer, thaw it by placing the sprayer in a warm area until completely thawed before starting. If paint has hardened, consider replacing the pump packings. Also, check the displacement pump connecting rod pin, pushing it into place and securing it with the spring retainer. If the fan still doesn’t turn, the motor may need replacing.
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Alex RamosAug 4, 2025
Why does my Graco Paint Sprayer motor run and pump strokes, but it's still not spraying?
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  Brad JenkinsAug 4, 2025
  If your Graco Paint Sprayer motor runs and the pump strokes, but it's not working correctly, ensure the prime valve is closed. Check the paint supply and refill and reprime the pump if necessary. Remove and clean the intake strainer, then reinstall it. Tighten the nut on the suction hose to prevent air leaks, and check the o-rings on the swivel. To ensure proper seating of the intake valve ball and piston ball, strain the paint before use to remove particles that could clog the pump. For leaks around the throat packing nut, which may indicate worn or damaged packings, or a damaged pump rod, consult the Pump Manual 309250.
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perezanneAug 14, 2025
What to do if my Graco 390 motor runs but the pump doesn't stroke?
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  David MillerAug 14, 2025
  If the Graco Paint Sprayer motor runs but the pump doesn't stroke, check the displacement pump pin for damage or if it's missing; replace it if necessary, ensuring the retaining spring is fully in the groove around the connecting rod. Inspect the connecting rod assembly for any damage and replace it if needed. Also, examine the drive housing assembly and gears for damage, replacing them if necessary.
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David MiddletonAug 19, 2025
Why is my Graco Paint Sprayer motor hot and running intermittently?
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  cmccoyAug 19, 2025
  If your Graco Paint Sprayer motor is hot and runs intermittently, first ensure the ambient temperature is not above 115°F (46°C) and the sprayer is not in direct sunlight; move it to a cooler, shaded area if necessary. If the motor has burned windings, indicated by burned commutator bars next to the positive brush, replace the motor. Also, check the tightness of the pump packing nut, loosening it and inspecting for leaks around the throat; replace the pump packings if needed.
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Maria DelgadoNov 8, 2025
Why is my Graco 390 Paint Sprayer having low output?
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  Denise WebbNov 8, 2025
  If your Graco Paint Sprayer exhibits low output, start by relieving the pressure and replacing the spray tip, as it may be worn. Ensure that the pump doesn't continue to stroke after releasing the gun trigger; if it does, service the pump. Check the prime valve for leaks and repair if necessary. Tighten any loose suction hose connections and inspect the o-rings on the suction hose swivel. Verify the electric supply by resetting the building circuit breaker or replacing the fuse, and try another outlet. Replace any incorrect extension cords with a grounded one of the correct size and length. Check the leads from the motor to the circuit board for damage or loose wire connectors, ensuring the terminals are firmly connected. Replace worn motor brushes, clean brush holders, and replace the pre...
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Steven SandersNov 23, 2025
How to troubleshoot basic electrical problems with my Graco 390 Paint Sprayer?
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  cindy60Nov 23, 2025
  If you're experiencing basic electrical issues with your Graco Paint Sprayer, start by resetting the building circuit breaker or replacing the fuses, and try a different outlet. Replace the extension cord if necessary. If the sprayer power supply cord is faulty, replace it. Replace the fuse after inspecting the motor. Ensure the motor leads are securely fastened and properly connected to the control board by replacing loose terminals and cleaning the circuit board terminals. If the motor thermal switch is the issue, replace the motor. Install the brush cap or replace the brushes if the brush lead connections are loose or damaged, and ensure the brush length is at least 1/4 inch (6mm); replace the brushes if they are shorter. If the motor armature commutator has burn spots, gouges, or extre...