How To Know When Your Unloader Valve Fails

Pressure pumps are complex, precise pieces of equipment, and they require routine maintenance and replacement of parts as they wear over time. One such part is the unloader valve; this component is vital for the proper operation of pumps that supply pressurized water on a demand basis. If you have a pump system that is malfunctioning, one place you should check for trouble is the unloader valve. Here is more information about how to diagnose problems with unloader valves and how to replace them should they fail:

What does an unloader valve do?

The unloader valve serves as a gatekeeper for the flow of pressurized water within a pump before it passes out of the exit hose and pressure nozzle. Unloader valves automatically regulate when water flows into the nozzle or recirculates back into a pump during periods of non-use. During non-use, the water inside the pump becomes a closed loop with no “new” water allowed to enter. Once the operator begins releasing pressurized water again, the unloader valve then stops closed circulation and allows freshwater to enter the system.

Pressure pumps use positive displacement technology, which simply means that water continuously moves through pumps, as opposed to impulse pumps which only operate in an on or off fashion. With positive displacement pumps, an unloader valve is necessary because it prevents the pump from building destructive internal pressures.

What happens when unloader valves fail?

A failing unloader valve is immediately noticeable because of its critical impact on the performance of pressure pumps. Unloader valves that aren’t working properly can cause these problems:

Control & Safety Valves

Controlling the flow of media in your process is often the single most important part of an operation. Typically made up of an actuator, positioned and body, Control Valves can manage flow, pressure, temperature, and level at the push of a button.

Processing product quickly, efficiently, and safely is more important than ever. Even short-term system failures can have major consequences. That’s why HydrovacTech works with the world’s finest brands in fluid motion and control products.

Our Control & Safety Valves Services

Evaluation and Inspection:

Our trained personnel can complete valve evaluations. Eliminate future issues and reduce downtime through early detection and analysis.

Preventative Maintenance:

Procedures such as proper greasing and packing adjustments ensure optimal operation for the long term, making sure you won’t have any surprises.


Our mobile, trained and fully equipped personnel provide quick, onsite repairs for common issues. If the job is too complex to be completed onsite, the valve will be shipped to our In-House service team for proper repair.


Valves require properly trained personnel to ensure the calibration and adjustments are completed correctly. Our technical staff is specifically trained to do so with elite-level precision to warrant a longer valve life.


Valves are complex parts of any process system, especially if they are actuated or part of a larger BUS or PLC
system. Startup commissioning is one way to ensure your valves are set properly once installed and are ready to perform.

Control Valve Support:

We are able to provide high-quality, experienced personnel that can troubleshoot, install, and repair these complex valve assemblies to ensure optimal performance.

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