Strange valve issue
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I installed a cylinder valve; after removing it for maintenance and reinstalling it, first the switching direction was reversed. Moreover, what was originally a gas-operated control valve now became a two-position valve – it can only be switched on or off, without any ability to adjust. Let the experts discuss what the reasons are.
It’s possible that the travel distance of the control valve or its zero point has been set incorrectly!
This post was last edited by jcicwht on 2009-7-10 07:50. The reversal in the on/off mode is due to the cylinder being installed in the wrong direction; it used to be possible to adjust it, but now it can only function as a two-position switch. This is because the on/off mode has changed, and the way the positioner operates also needs to be adjusted accordingly.
It’s possible that the two pistons on either side of the cylinder were installed in the wrong order, resulting in the rotation direction being opposite to before; reinstalling them correctly will fix the issue
We haven’t used this type of valve either.
Start with something simple – debug the locator to see the direction of the output pressure. It’s not too late to disassemble it after confirming the installation issue
I’m not quite sure what the author meant by their last few sentences:: It’s now a two-position type, meaning it can only be turned on or off, with no possibility of adjustment. Does that mean it has changed from a valve that operates via air pressure to shut it off to one that operates via air pressure to turn it on? (Piston-type pneumatic actuators are usually single-acting.) If that’s the case, all that’s needed is to set the initial state of the valve to open, and then install the pneumatic actuator – that should solve the problem! I’m not sure whether the author installed a positioner on the cylinder valve from the beginning. If you find it convenient, feel free to contact me! QQ: 928976489 (Your control valve consultant)
There should be no problem with the control valve; there are two possible reasons for this – one is incorrect installation, and the other is a problem with the actuator. It is recommended to try adjusting or replacing the actuator first; if the problem persists, reinstall it.
Our current plan is also to reinstall the valve, but since it’s about to be put into use, we can only wait until the next shutdown to do it. If the valve can only be opened and closed, it will lead to water waste, but given the urgency of the situation, there’s nothing we can do.
1. If the cam plate of the positioner is installed in the wrong direction, a \"two-position\" condition may occur. 2. The zero point and range settings of the positioner have been set incorrectly. 3. The positive and negative connections of the positioner have been reversed
It can no longer be adjusted; it has become a two-digit format. It’s possible that you have connected the air supply pipeline incorrectly; if the pipeline is connected properly, then it’s almost certainly a fault with the regulator.