Took over servicing an apartment complex last year and have been dealing with its wiring nightmares ever since. Basic rundown: two 13 strands left controller and spliced into 39 single strand wires. I have already remedied that situation. Now each single strand has it's own wire in the controller. Most zones comprise of multiple valves, some as many as 5 valves. Zone 8 has 3 valves all wired in series on one wire Zone 20 has 2 valves all wired in series on one wire Zone 27 has 3 valves all wired in series on one wire Zone 8 and 20 activate as expected. The problem; when I activate zone 27, I get the valves I want, plus one valve from zone 8 and also one valve from zone 20. Zone 27 activates 5 valves in total. For the life of me I cannot figure out how this possible. No known doublers. No known add-a-zones. Somehow these wires are all tied together, but why wouldn't zone 8 or 20 activate the valves of zone 27 then?