The motorized valve always came with hand wheel also. I just queries, that what will happen if the motorized valve don't work & can it open manually ?
depending of how the actuator (electrical motorize device) is constructed. Most larger, well equipped actuators will have a handwheel as a standard, but not all.
Some smaller 90. deg. electrical actuators without handwheel might be constructed with square spindle allowing movement 90 deg by wrench or similar.
Advice when specifying: 'with handwheel for manual operation' to be included as one of the specifications.
And to answer your question: if not equipped with handwheel or for wrench operation: you will have to demount the actuator to free the valve spindel for manual operation. In some cases this could be unsafe as the actuator could be an active element in the locking in place and/or sealing of the valve.

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