A flow meter is, in the simplest terms, a device that is used to measure the volume or mass of a gas or liquid moving through a pipe or other conduit. There are multiple types of flow meters, including Coriolis flow meters, Ultrasonic flow meters, DP flow meters, magnetic flow meters, vortex flow meters, and more. Calibration issues and inaccurate readings from flow meters can be caused by a wide range of problems, leading to decreased product quality and system inefficiencies. In this article, we’ll go over some of the most common causes of inaccuracy problems with flow meters of all kinds! If you’re experiencing a flow meter calibration issue within a system in your facility, Sentrol Inc. provides repair and calibration services for the industrial manufacturing markets in New England, the Mid-Atlantic, & Eastern Canada! Contact us today!


One of the most common causes of an inaccurate flow meter reading is the presence of rust within the system’s pipes. Rust can occur when pipes that are not in use come into contact with air, causing oxidation. When these pipes come back into use, the liquid flow can cause the rust to flake off and clog inside the flow meter, causing inaccurate readings.

Air Bubbles

Air bubbles commonly cause inaccurate flow meter readings in open systems. Air can be introduced into the system during liquid intake, causing misreadings with vortex flow meters, ultrasonic flow meters, and electromagnetic flow meters because the air bubbles get mistaken for fluid.


Scaling in a flow meter occurs when metallic ions crystalize and become attached to the walls of the piping. As these crystalized metallic ions build up, the pipe essentially gets narrower and restricts flow. Thick layers of scaling can also make electromagnetic flow meters unable to detect the voltage that has been generated, causing inaccurate readings.

Irregular or Pulsating Flows

One more common cause of inaccurate flow meter readings is an irregular or inconsistent flow. Irregular flows can be caused by a wide variety of things, including bends in the piping and changes in pipe diameter. Irregular flows can often be fixed by installing a straight pipe section upstream from the flow meter, making the distribution of the flow velocity more uniform. Pulsating flows can be caused by volume type reciprocating pumps, leading to readings that are smaller than reality. Pulsating flows can sometimes be fixed using an accumulator or by increasing your flow meter’s response time.

Contact Sentrol Inc!

Contact Sentrol Inc. today to learn more about the instrument repair and calibration services we provide for flow meters, control valves, pressure regulators, analyzers and more in the manufacturing markets of New England, the Mid-Atlantic, & Eastern Canada! Give us a call today at (888) 877-1778 or fill out the contact form on our website, and a member of our team will get back to you as soon as possible!