I am attempting to resurrect an older in-ground sprinkler system. I have uncovered three Nelson P/N 3022039 control valves. The existing timer is an old Nelson C-5. My plan would be to replace the timer with a modern unit and use the existing valves assuming they still operate. Are these valves any good? How old are these parts? Any input from the experts? It would appear I have a three zone system. What timer would you recommend? What is the wire lead labeled common on the timer? Is this the 24...