What are the common faults of differential pressure transmitters, and how to diagnose them?

Differential pressure transmitters are widely used in industrial measurement, commonly for monitoring flow, level, and pressure differences. Due to complex operating conditions, they are prone to problems such as no output, large numerical deviations, and signal fluctuations during long-term operation. To quickly diagnose the fault, it is usually necessary to check the power supply, wiring, pressure lines, and sensor step by step to find the root cause before taking action.

 

Why does a differential pressure transmitter have no output?

When the transmitter has no output, first check if the power supply is normal and if the wiring terminals are loose or broken. Then check if the pressure lines are blocked, if the valves are open, and if the balancing valve is in the correct position. If the power supply, wiring, and piping are all normal, then consider damage to the transmitter’s internal circuitry or sensor.

 

Why are differential pressure transmitter readings too high or too low?

Abnormal readings are usually related to the pressure-conducting system. For example, reversed high and low pressure connections, gas or liquid in the pressure lines, and pipeline leaks can all affect the measurement results. Also check for zero-point drift, correct installation location, and whether there are deposits clogging the pressure tap. Often, the problem isn’t with the instrument itself, but with the external connections.

 

Why is the differential pressure transmitter output unstable?

If the output value fluctuates, first check if the operating conditions are inherently unstable, such as large changes in medium flow or significant pressure pulsations. Next, check for poor wiring connections, intermittent short circuits, or grounding issues. Gas or liquid mixed in the pressure-conducting pipe, or excessive installation vibration, can also cause signal instability.

 

How to quickly pinpoint the fault?

When troubleshooting, follow the principle of “external to internal, simple to complex.” First, check the appearance, wiring, power supply, valves, and pressure-conducting pipes. Then measure whether the output current is within the normal range. If there is a significant difference between the measured value on-site and the value displayed by the control system, it usually indicates a problem with the pressure-conducting pipes or the transmitter itself. If necessary, use the substitution method to temporarily replace the suspected component for verification.

 

How to reduce daily malfunctions?

Regularly check the pressure-conducting pipes for blockages and leaks, the terminals for oxidation and loosening, and the zero point for drift. For humid, corrosive, or high-vibration environments, strengthen protection and inspection. Proper installation, regular calibration, and timely cleaning of the pressure taps can significantly reduce the probability of failure.

 

The key to diagnosing differential pressure transmitter faults lies in grasping the core aspects of “power supply, wiring, pressure-conducting pipes, and calibration.” In daily maintenance, regularly checking for loose wiring, blocked pipes, and zero point drift can effectively reduce the occurrence of faults. Proper installation, appropriate model selection, and timely maintenance not only improve measurement stability but also extend the equipment’s lifespan. An Hui Exact has extensive experience in the pressure transmitter industry and boasts several experienced experts to meet your diverse scenario and product needs.