The butterfly valve won’t open! Help! !
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The DN500 butterfly valve has been installed on the pipeline, but it now won’t open! ! Later, I used a wrench to turn it slowly, and after some effort I managed to rotate the handle; the pointer also reached 90. However, when water flowed through it, there was no sound of water flow. Since it’s a heating system, the water is hot, so the upper half of the valve is hot while the lower half remains cold... How can this problem be solved? ? It’s extremely urgent... Are there any ways to improve it other than replacing the valve? Urgently need expert help!
Large new butterfly valves are indeed difficult to open under operating conditions due to the pressure of the fluid in the pipeline. In the situation you described, it’s possible that the butterfly valve isn’t open; its rotating shaft is slipping, and it can only be replaced.
It’s likely that you’ve damaged it, so the valve stem can no longer drive the butterfly valve.
Was it not installed properly? Are the attachments and such installed? Can the air source pressure to open the valve also be achieved? If the air source pressure is not sufficient, it is difficult to open the valve
It’s probably the turbine slipping, or the bolt has come loose
Does this butterfly valve have a cylinder? It was difficult to turn the handle to 90 degrees, but the valve didn’t actually move – could it be that the connection at the bottom is misaligned? One last question: when this valve is opened, is the pressure difference between the upstream and downstream sides significant? Is it about pressurizing?
The valve is not open; open the valve cover at the pointer, and you will be able to see the turbine mechanism inside the handwheel. Try to open it using pipe wrenches
For a butterfly valve of such a large diameter, with the pointer indicating 90 degrees as you described, it is assumed that it has an actuation mechanism equipped with a turbine head. The valve is currently in the closed position, and the reasons why it cannot be opened can be analyzed as follows: 1. The valve has not been used for a long time, resulting in the sealing ring of the butterfly disc sticking to the valve body. At the same time, when the valve is exposed to high temperatures, the upward and downward rotation clearance of the valve stem is too small, causing the stem to get stuck inside; as a result, it is very difficult to open the valve, or it may not open at all. 2. The turbine head fitted to the valve has a low opening torque, resulting in insufficient force for opening it; generally, when valves leave the factory after testing, workers use F-wrenches to apply strong force, which causes them to close too tightly. The solution now is, first, to stop the machine and balance the temperature on both sides of the valve; then, using an F wrench to apply force, try to open it and see if it can be opened. At the same time, without any pressure, it is also possible to loosen the packing and give it a try; if that doesn’t work, the only option left is to remove it and replace it with a new valve.
Butterfly valves should open and close easily. Check the actuator to see if the bearings are damaged. Also, do not force the valve to open if it won’t move – this can easily cause damage. If significant force is still needed to open it, it’s best to disassemble it and check for any blockages or obstructions; once those issues are resolved, then try to open and close the valve again