How To Troubleshoot Mechanical Water Valve Problems?

How To Troubleshoot Mechanical Water Valve Problems?

It does not matter how much a mechanical valve is capable, a time comes when it will show some limitations in flowing fluids through it. Its performance will absolutely show a decline with the passage of time. Often the issues are captured through the naked eye, but the technical mechanical problems are very difficult to troubleshoot in person. Whether you are using a new or an old pneumatic proportional valve, it will stop working at a particular time when its life ends due to certain causes. Here in this blog, we will share some of the major causes of valve failure.

Dead Band:

When a pneumatic proportional valve stops working completely, it is considered a dead band. In this situation, there is no output against the input which means the valve will not allow the fluid to flow through it.  In such a situation, a couple of possibilities arise. Whether you can change the direction of the valve install a brand new one in place of it. 



  • The controller signal coming through the valve is not given by it or shows pulses
  • The valve gives a reverse thrust every time it is initiated to flow the fluid through it 

High Dead Band:


  • System dead time is increased too much
  • Uneven or sudden flow and blockages one after the other 


When the direction of flow is changed due to a dead band, it needs to be elongated before any drastic issue happens. But in certain conditions, a dead band is very useful. But if your pneumatic proportional valve is stuck with this condition, you must instantly change it before it gets burst due to high air pressure.


Stiction arises due to excessive friction between the valve spool seal and its body. It is another major cause that leads to valve failure. Basically, when a pneumatic proportional valve is in a sticky situation, it neither goes forward nor backward and gets stuck where ever it is. In this condition, extra power is required to drive the valve. And when this extra force is applied, the chances are there that it will let the digital flow valve burst or set up in a new wrong position. 


If the output of the controller moves periodically more than 0.5% in every cycle, then there is a problem like sticking. In such a condition, the following symptoms are troubleshot:


  • Actuators of the valve get undersized 
  • The viscosity of the media passing through it gets increased
  • During stiction, the valve is not capable of meeting the set pressure
  • The movement of the valve loop will be like a saw-tooth wave


To fix the problem, make sure that the actuator and positioner of the valve are sized to provide maximum pressure throw to the fluid in order to flow.

Wrapping It Up:

Every fluid control valve that is manufactured has some limitations. Where one piece shows no working in pone certain condition, any other valve may show no working in another condition. That is why while installing a pneumatic proportional flow control valve in a system, make sure it is a piece sufficient to meet the desired pressure needs in a piping system.

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