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Graco 390 PC - User Manual

Graco 390 PC
50 pages
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334567E
EN
Operation, Parts
Electric Airless
Sprayers
For professional use only.
Not approved for use in explosive atmospheres or hazardous locations.
For portable airless spraying of architectural paints and coatings.
190/290/390 PC Classic Models:
3000 psi (207 bar, 20.7 MPa) Maximum Working Pressure
3300 psi (228 bar, 22.8 MPa) Maximum Working Pressure
See page 3 for additional model information.
Important Safety Instructions
Read all warnings and instructions in this manual and related manuals. Be familiar with
the controls and the proper usage of the equipment. Save these instructions.
Related Manuals
Gun – 311861 (Contractor/FTx) 312830 (SG3) Pump – 334599
ti25126a
Use only genuine Graco replacement parts.
The use of non-Graco replacement parts may void warranty.

Table of Contents

Questions and Answers

  • H
    Heather AcostaAug 15, 2025
    What to do if fluid is spitting from my Graco Paint Sprayer gun?
    • A
      alexandrawrightAug 15, 2025
      If your Graco Paint Sprayer is spitting fluid, it could be due to a few reasons. There might be air in the pump or hose; check and tighten all fluid connections, and cycle the pump slowly during priming. Also, the spray tip could be partially clogged; clear the tip. Finally, the fluid supply might be low or empty; refill the fluid supply and prime the pump, checking the fluid supply often to prevent running the pump dry.
  • S
    Stephen MorganAug 18, 2025
    Why is my Graco 390 PC Paint Sprayer pump difficult to prime?
    • R
      Robert PerezAug 18, 2025
      If your Graco Paint Sprayer is difficult to prime, it could be due to several reasons. There might be air in the pump or hose. In this case, check and tighten all fluid connections and cycle the pump as slowly as possible during priming. Another cause might be a leaking intake valve. Clean the intake valve, ensuring the ball seat is not nicked or worn and that the ball seats well; then, reassemble the valve. Also, worn pump packings can cause priming issues; in this case, replace the pump packings. Finally, if the paint is too thick, thin it according to the supplier's recommendations.
  • G
    Gina WashingtonAug 22, 2025
    How to fix excessive paint leakage into the throat packing nut of my Graco 390 PC?
    • J
      Jesse MoranAug 22, 2025
      If your Graco Paint Sprayer experiences excessive paint leakage into the throat packing nut, it could be because the throat packing nut is loose. Remove the throat packing nut spacer and tighten the throat packing nut just enough to stop the leakage. Another possibility is that the throat packings are worn or damaged, in this case replace packings. In other case, the displacement rod is worn or damaged, in this case replace the rod.
  • W
    walterericaAug 28, 2025
    What to do if the motor runs but the pump doesn't stroke on my Graco 390 PC?
    • F
      Felicia HamiltonAug 28, 2025
      If your Graco Paint Sprayer motor runs but the pump does not stroke, it could be due to a damaged connecting rod assembly. In this case, replace the connecting rod assembly. Another possible cause is damaged gears or drive housing. Inspect the drive housing assembly and gears for damage and replace if necessary.
  • M
    Mary HunterAug 31, 2025
    Why does my Graco 390 PC stop after running for only 5 to 10 minutes?
    • E
      Edward WhitakerAug 31, 2025
      If your Graco Paint Sprayer operates for only 5 to 10 minutes and then stops, the pump packing nut might be too tight. When the pump packing nut is too tight, the packings on the pump rod restrict pump action and overload the motor. Loosen the pump packing nut and check for leaks around the throat. If necessary, replace the pump packings.
  • N
    Nicole CookSep 4, 2025
    What to do if my Graco Paint Sprayer will not shut off after reaching maximum pressure?
    • B
      Briana CrosbySep 4, 2025
      If your Graco Paint Sprayer will not shut off after reaching or exceeding maximum pressure, check the pressure control. Disconnect the pressure control; if the sprayer still runs, replace the control board. If the sprayer stops, replace the pressure control.
  • S
    Scott WilkersonSep 7, 2025
    Why does my Graco 390 PC Paint Sprayer not run at all?
    • M
      Matthew RodriguezSep 7, 2025
      If your Graco Paint Sprayer does not run at all, check the electrical supply, pressure control connections, pressure control, replaceable fuse, and motor leads. Ensure that there is AC voltage: 100-130V for 110-120VAC models or 210-255V for 230VAC models.
  • K
    Kelly SmithSep 12, 2025
    How to troubleshoot basic electrical problems with my Graco 390 PC Paint Sprayer?
    • W
      william39Sep 12, 2025
      For basic electrical problems with your Graco Paint Sprayer, ensure the motor leads are securely fastened and properly mated. Replace loose terminals and crimp them to the leads, ensuring they are firmly connected. Clean the circuit board terminals and securely reconnect the leads.
  • J
    jordanmarkNov 24, 2025
    Why is the pump output low on my Graco Paint Sprayer?
    • A
      Amanda CamposNov 24, 2025
      If your Graco Paint Sprayer's pump output is low, several factors could be the cause. First, the spray tip might be worn; in this case, relieve the pressure and replace the tip. A clogged spray tip is another possibility; relieve the pressure and clean the spray tip. Ensure that the paint supply is adequate by refilling and repriming the pump. Also, check for a clogged intake strainer, and if found, remove, clean, and reinstall it. If the intake valve ball and piston ball aren't seating properly, remove the intake valve and clean it, inspecting the balls and seats for damage. Additionally, a clogged fluid filter or tip filter can cause low output, so clean the filter. A leaking prime valve can also be the reason; relieve the pressure and repair the prime valve. Also, leaking around the thr...

Summary

Electric Airless Sprayers

Important Safety Instructions

Key safety guidelines and warnings for operating the equipment.

Warnings - Grounding

Grounding and Extension Cord Safety

Essential safety information regarding proper grounding and extension cord usage.

Warnings - Fire and Explosion

Fire and Explosion Hazard Prevention

Guidelines to prevent ignition of flammable fumes and materials during spraying.

Warnings - Personal Safety

Skin Injection and Equipment Misuse Hazards

Warnings related to high-pressure injection and improper equipment operation.

Warnings - Electrical and Toxic

Electrical Shock and Toxic Fluid Risks

Hazards associated with electrical shock, toxic fluids, fumes, and PPE.

Grounding Procedures

Power Requirements and Pail Grounding

Details on grounding, power needs, and pail usage for safety.

Pressure Relief Procedure

Pressure Relief Steps

Step-by-step instructions for safely relieving pressure in the sprayer.

Trigger Lock Operation

Setup Procedure

Initial Sprayer Setup

Startup Procedure

Sprayer Startup and Priming

Maintenance

Routine Maintenance Schedule

Table outlining activities and intervals for sprayer maintenance.

Troubleshooting - Mechanical;Fluid

Mechanical and Fluid Flow Issues

Diagnosing and resolving problems related to mechanical or fluid flow.

Troubleshooting - Electrical

Electrical Issues and Solutions

Troubleshooting steps for common electrical problems like not running or shutting off.

Graco 390 PC Specifications

General IconGeneral
Max Pressure3300 PSI
Flow Rate0.47 GPM
Motor TypeDC
TypeAirless Paint Sprayer
Power SourceElectric
Voltage120 V
Hose Length50 ft
Max Tip Size0.021 in
Horsepower0.625 HP
Weight30 lbs

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