Bleed valve or replace/repair?
Interesting forum, glad I found it. Hopefully I can contribute eventually.
This may get a little long so I can completely cover the situation. Anyway, I have inherited a sprinkler system with my house. It's an older system, mainly Toro valves (?250/60 series? I have replaced a couple with Rainbirds), 5 zones, installed by the original owner long ago. The previous owners to me re-landscaped the yard, buried all the valves and didn't mark them. So over the last couple of years sections have been failing and I locate the valve for that section and repair it by rewiring, replacing solenoid, repairing valve, whatever. So, from this house and several systems I have put in/repaired for friends and family, I have some experience in most aspects of testing and fixing valve troubles.
However, I have one now that I am not quite sure of. As in previous cases, two sections quit working. The valves are close together and it makes sense that they both went out since they both were buried and overgrown with roots. I redid the wire connections, verified 24 volts, replaced the solenoids and verified that they were in fact actuating at the valve.
Now, the trouble is that the valves seem to either not open fully or have some kind of an air lock in them. I have taken them apart and cleaned then to verify that there are no debris in there. In both cases, you can hear water running through the valve but it sounds like a faucet that is barely cracked. The zones will come on if you open the bleeder ALL THE WAY. One of the zones shuts of when you close the bleeder (can still hear the water running though) while the other zone will stay on for a bit, then you can hear the rush of air/turbulence/whatever and the valve closes (can still hear the water running though). If I mess with the second one by turning the bleeder on and off, it will eventually stay on when the bleeder is closed. Further, if I leave the second zone on long enough (bleeder closed), it will eventually build up pressure and the section will come on.
I <i>almost</i> sure that there are not leaks in the lines. My soil is fairly dense and any leaks in the past have been easy to see. That and given the layout of my yard, any leak that didn't show up in the yard, would eventually be seen running down the street. My initial guess is that is the diaphragms. Not allowing the valve to open in one case and not completely sealing in the other and letting all of the water to drain out of the zone. Normally, I would just completely replace the valves. However, remember all that landscaping I mentioned? Well these valves are located right in the middle of a large bush that I have to crawl around under to work on this. Not much room to dig out a large enough hole to do it right. Moving them completely is another option, but not one I want to mess with right now.
Thanks for any input
Scott
