My sprinkler system has multiple zones. There is a problem in the "handoff" between 2 and 3. When the cycles are run normally, 1 and 2 work great but the pressure to 3 is so low that the sprinkler heads do not pop all the way up. However, if I run 3 manually, the pressure is there and they pop all the way up. How do I fix what appears to be a transition problem between 2 and 3?