We have a 8 inch velan switch valve that has started sticking and must be hand jacked to switch. We have a steam purge that is not working and believe that it has coke (not oil) in it.
Any info/help would be greatly appreciated.
Also, we are worried about what to do if the valve gets stuck in half switch and we are not able to make a full switch or go to bypass. I myself have a few ideas but desperatly need more info on the valve sticking and procedures for a stuck valve in the middle of a switch.
1. You said the valve is operable by hand. The actuator/motor could be bad.
2. If the valve got switched without proper steam pressure, then the resid can get into the cavity. If this is the case it wont be long before this resid get hard inside and makes the valve inoperable.