Testing the Pressure Washer Pressure Switch with a Multimeter

Pressure Washer Dies When I Let Off the Trigger

November 1, 2024 By Alisson

If your pressure washer dies when you let off the trigger, you’re likely experiencing a common issue that can be frustrating but often easily fixed. This problem typically stems from issues with the unloader valve, the pressure switch, or occasionally, other components like a faulty O-ring or inlet filter. Let’s explore the potential culprits and how to troubleshoot them.

Understanding Why Your Pressure Washer Dies When You Release the Trigger

When you squeeze the trigger on a pressure washer, water flows and the pump builds pressure. When you release the trigger, the flow stops, and the pressure needs to be managed. This is where the unloader valve comes into play. It diverts the water flow back into the pump’s inlet or outlet, relieving the pressure. If this valve isn’t functioning correctly, the pressure can build up and cause the engine to stall. Similarly, a malfunctioning pressure switch, which controls the power to the pump based on pressure readings, can also lead to this problem.

Common Causes and Troubleshooting Steps

Unloader Valve Problems

The unloader valve is the most frequent culprit when a pressure washer dies when the trigger is released. Here’s what to check:

  • Type of Unloader Valve: There are two main types: thermal relief valves and pressure relief valves. Knowing your type is crucial for accurate diagnosis.
  • Adjustments: Some unloader valves are adjustable. Try adjusting the screw (usually found on the top) slightly to see if it resolves the issue. Remember to turn it only a small amount at a time and test after each adjustment.
  • Blockage: Debris or mineral buildup can obstruct the valve. Disassemble and clean it thoroughly.
  • Damaged Parts: Check the valve for worn-out springs, seals, or other damaged components. Replace any damaged parts.

Pressure Switch Issues

The pressure switch tells the motor when to turn on and off based on the pressure. If faulty, it can cut off power prematurely.

  • Electrical Connections: Ensure the wires connected to the pressure switch are secure and free from corrosion.
  • Testing the Switch: You can use a multimeter to test the continuity of the pressure switch. If it’s not functioning correctly, it needs replacement.

Testing the Pressure Washer Pressure Switch with a MultimeterTesting the Pressure Washer Pressure Switch with a Multimeter

Other Potential Issues

While less common, these issues can also cause your pressure washer to die when you release the trigger:

  • O-rings: Damaged O-rings can lead to pressure leaks, which can sometimes mimic unloader valve problems. Inspect and replace any worn or damaged O-rings.
  • Inlet Filter: A clogged inlet filter restricts water flow, potentially causing the engine to stall. Clean or replace the filter.
  • Low Engine Speed: Ensure the engine is running at the correct RPM.

Preventing Future Problems

Regular maintenance can help prevent this issue:

  • Flush the Pump: After each use, run clear water through the pump for a few minutes to remove debris.
  • Use a Pump Saver: A pump saver lubricates the internal components and prevents freezing.
  • Store Properly: Store the pressure washer in a dry, protected area.

Conclusion

When your pressure washer dies when you let off the trigger, the most likely culprit is the unloader valve or pressure switch. By following the troubleshooting steps outlined above, you can often identify and fix the problem yourself. Regular maintenance can help prevent future occurrences of this issue, ensuring your pressure washer operates smoothly for years to come.

FAQ

  1. What is the unloader valve? The unloader valve regulates pressure within the pressure washer pump when the trigger is released.
  2. How do I know if my pressure switch is bad? Test it with a multimeter for continuity.
  3. Can I fix the unloader valve myself? Often, yes. Cleaning or replacing parts is usually straightforward.
  4. Why is regular maintenance important? It prevents premature wear and tear and keeps the pressure washer running efficiently.
  5. What is a pump saver? A pump saver is a lubricant that protects the pump from damage during storage, especially in freezing temperatures.
  6. How often should I clean the inlet filter? Check and clean the inlet filter regularly, especially if you use the pressure washer frequently or in dirty environments.
  7. My pressure washer still dies after trying these fixes. What should I do? If the problem persists, it’s best to consult a qualified pressure washer repair technician.

Common Scenarios

  • Scenario 1: Pressure washer shuts off immediately upon releasing the trigger. This often points to an unloader valve issue.
  • Scenario 2: Pressure washer runs for a few seconds after releasing the trigger then shuts off. This could indicate a problem with the pressure switch or a slow leak.

Related Articles

  • Troubleshooting Pressure Washer Issues
  • Maintaining Your Pressure Washer for Optimal Performance

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