Zone won't come on unless bleeder valve is opened
We have a 6-zone system. Zone 2, an Irritrol 2623 3/4" valve, does not open in the cycle, while the other zones (with same valve model) work correctly.
This valve has a little screw for the bleeder valve.
If I open the bleeder valve with the zone off, the sprinklers come on after a few seconds, and stay on until I close the bleeder valve.
If I open the bleeder valve with the zone on (say, manual on for 20 minutes), the sprinklers come on. After a few seconds, I can close the bleeder valves and the sprinklers stay on until the controller shuts off the zone.
In both cases the sprayheads have full water pressure and appear to be working normally.
I just can't get the zone to come on automatically, without manually opening the bleed valve to get it started.
I guess/hope wiring is OK (controller can shut off zone, and start it with my help). It looks like I need to shut off the house water supply and open up/replace the valve. Any ideas?
Thanks!