Solution for solenoid valve with can give flow without power? or any other alternative way of it?
Use something like this that's rated for whatever flow you need:

https://www.ebay.com/i/271982596560?chn=ps&amp;dispItem=1

The blue knob at the back is a pull that allows the valve to manually actuate. You can also place an AC or DC coil over the valve to energize it electrically from a micro/plc/etc.