Buying from e-bay a common valve usually is not gravity feed.
Needs a lot of pressure in order to allow the water to flow when the coil is energized.
The tools that we are going to need in order to make this modification are :
A glue gun
A straw
A water bottle
Tape
A diode
A screw driver
A dremel with 1.7 mm drill bit
A 12V 1A AC to DC adapter / power supply
...continue reading "Converting a normal water valve into a gravity feed valve"