If you’ve ever wondered how your pressure washer safely handles water flow when you’re not pulling the trigger, the unloader valve is the key component behind the scenes.
Types of Unloader Valves
There are two main types of unloader valves: built-in and external. Both serve the same purpose but differ in design:
- Built-in Unloader Valves: Bypasses water through a brass channel integrated into the pressure washer.
- External Unloader Valves: Bypasses water through an external bypass hose, typically 12”-18” long, which leads back to the inlet side of the pump. This type is often easier to adjust and service.
What is the job of the Unloader Valve?
The unloader valve regulates water flow within a pressure washer. While the machine is running and the trigger is pulled, the unloader valve allows the washer to operate at full pressure without diverting any water. When the operator releases the trigger, pressure builds up and overcomes the spring tension, forcing the unloader valve to redirect water to the low-pressure side of the pump. This process prevents pressure from continuing to build inside the system.
Does the Unloader Valve Need to Be Adjusted?
Yes, it’s critical that the unloader valve is properly adjusted to maintain the pressure washer’s efficiency and safety. When the trigger is pulled, the valve should allow full pressure without bypassing water. If the spring tension is too loose, the valve could bypass water. However, if the spring tension is set too high, the unloader valve may not properly engage when the trigger is released, causing damage. It is recommended to regularly check the valve’s adjustment to ensure optimal pressure and safe operation.
How Long Can a Pressure Washer Run in Bypass?
When the pressure washer is in bypass mode (when the trigger is released), water circulates rapidly from the high-pressure side to the low-pressure side of the pump. This creates friction, which generates heat. Over time, that heat can damage vital components like water seals and check valves.
Every pressure washer should have a thermal relief valve to help protect it from overheating. However, a good rule of thumb is to avoid letting the machine run in bypass mode for more than a minute. If you need to pause longer than that, it’s better to turn off the machine and restart it when you’re ready to resume.
Conclusion
The unloader valve is an essential component of your pressure washer, allowing it to handle pressure fluctuations safely. Whether built-in or external, its role is the same: to protect the pump and maintain efficient operation. Make sure it’s properly adjusted, and always be mindful of how long your machine runs in bypass mode to prevent heat-related damage. By understanding how your unloader valve works and ensuring it’s properly maintained, you can extend the life of your pressure washer and ensure it’s always ready for the next job.