The easiest way to know if a pressure regulator works correctly is to install a pressure gauge on each side of the regulator. You can measure the inlet pressure with a pressure gauge above the regulator, and the outlet pressure with a gauge below the regulator, as shown in the image below.
As a rule of thumb, if a pressure regulator delivers an outlet pressure significantly above its rating, you should consider replacing it. However, note that pressure regulators are typically rated for an accuracy of +/- a certain percent. It’s important to check the manufacturer’s documents to determine how much variation is permissible and/or expected.
For example, a 15 psi (1.03 bar) Senninger pressure regulator delivering an outlet pressure of 20 psi (1.38 bar) would be regarded as malfunctioning because our regulators have an accuracy of +/- 6 percent.
The best way to ensure a Senninger pressure regulator is working as designed is to download the SennREG mobile app and input your output reading into the app’s calculator. SennREG will then show you if a pressure regulator is operating within range, nearing the end of their life, or if it needs to be replaced.
A Word of Caution
Pressure gauges can provide an accurate reading, but getting gauges installed on several test drops is a time-consuming process. If you have a center pivot, you need to dismantle each hose drop to remove its components and install the gauges above and below the pressure regulator. Then, you must restart the pivot and read each individual gauge.
Depending on the size of the pivot, a grower could have anywhere between 5 and 15 drops to test to get an accurate picture of the system’s pressure regulation status.
Going in-depth into pressure regulator fundamentals
Learn the fundamentals of pressure regulation with Senninger's free on-demand Pressure Regulation course on Hunter University. Learn how to identify wear issues, causes of pressure fluctuations, install pressure regulators in different irrigation systems, select a model and more.