Question
When I put the timer on manual on zone 4 it will not go off, but yet I can turn on zone 3 that's on the same valve on and off while zone 4 is still on. To turn off the water on zone 4 I have to go to the main water valve and turn it off. At first it was intermittent, but now it just stays on. Do you think it's the processor or the valve?

Answer
Hi Frank

The problem is at the valve. First could be a loose or wearer selenoid, so thigh it or replace. Also check for the bleed assy, the small piece between the selenoid and the valve its usually  broke. These are the most common causes. If the selenoid and and the bleed assy are fine the problem is inside the valve, open it and clean the diaphragm or replace it if is broken.

Regards
Guillermo