How can the weight of the water from L be enough to to provide pressure to fill F ?
Because the inlet pipe of L is the same height as the top of F
Fluid in gravity always seeks equilibrium. Water, in this case, will be flowing into L via gravity at enough rate to overcome surface tension when F hit's the brim. Even if it is only a drip coming out of the faucet.. So, no pressure or high flow needed and nothing goes anywhere else. Unless the flow from the faucet exceeds the capacity of the outflow pipe of A.
The pipe from C to J is the same diameter of the outlet pipe from J to L. So I will never fill.
For the record, these puzzles are not science or engineering but mental exercises DESIGNED to improve memory. As a result, my observations have created a headache. I'm 70 YEARS OLD. Doc, I beg you,,,; PLEASE STOP!