Wilden Products

Durability, Reliability and Cost Savings

Not only are Wilden pumps the most cost-effective, reliable and energy-efficient solutions available, but our state-of-the-art air distribution systems (ADS) significantly increase positive displacement pump productivity by reducing air consumption and maintenance for the most energy-efficient AODD pump operation possible.

View Our Products

Chem-Fuse Savings Calculator

Personalized savings calculations for your operation

Instantly see your potential savings based on the pre-filled standard mean time between failure data for Chem-Fuse and Conventional Diaphragms.

Start Saving Now

Specialty Series

View All

Wilden Markets

Wilden® solves pumping challenges across the spectrum

Wilden® positive displacement air-operated double-diaphragm (AODD) pump solutions are leading the way in a host of industries and applications.

View Our Markets

Wilden Support

The Wilden World of Service and Support - Assistance Beyond Expectations

Wilden® is always ready to assist with technical support for Wilden AODD pumps, parts or accessories.

View Our Support Options

Chem-Fuse Savings Calculator

Personalized savings calculations for your operation

Instantly see your potential savings based on the pre-filled standard mean time between failure data for Chem-Fuse and Conventional Diaphragms.

Start Saving Now

How To Correctly Set the Internal Relief Valve on a Hydraulic Diaphragm Metering Pump

by PSG | Jun 15, 2023

Since 1961, Neptune® has been known for providing accurate hydraulic metering pumps designed to handle critical applications in various industries, including agriculture, oil and gas, chemical processing, and water and wastewater treatment. However, the internal relief valve must be adjusted correctly for these pumps to perform optimally in these demanding applications.

The following step-by-step guide, part of our ProTip Series, will help you properly set the internal relief valve of Neptune 500, 560, 600 and 6000 Series Hydraulic Metering Pumps.

Step 1
Locate the relief valve. Note: Depending on the particular model, the relief valve will be positioned either at the top or bottom portion of the pump.


Step 2 Unscrew the relief valve cap to reveal a threaded hole leading to a 3/16” adjustment screw.


Step 3 Place a 3/16” Allen wrench onto the relief valve adjustment screw.


Final Step While keeping an eye on the pressure gauge, turn the Allen wrench clockwise, increasing the pressure until it reaches the desired setting. Note: The internal relief valve pressure should be 100 psi above the discharge pressure. For example, if pumping at 150 psi, the relief valve should be set at 250 psi.


Once the pressure is correctly set, your Neptune hydraulic diaphragm metering pump is ready to start pumping.

Although setting the relief valve is similar for all models, please refer to your specific pump manual for detailed maintenance and safety instructions.

Watch this video to see a Neptune product specialist demonstrate how to correctly set the internal relief valve of a hydraulic diaphragm metering pump.