SPRINKLER TALK FORUM - You Got Questions, We've Got Answers

If the problem is after your zone valve, such as a clogged or pinched line, there is a couple of things you can do. First of all, if the zone worked properly this spring, a pinched line is pretty unlikely, but still a possibility. If the line is clogged, you will need to remove the sprinkler heads from that zone and flush the line of any debris. If none of the sprinkler heads pop up at all, you know the clog or pinch is somewhere between the valve and the first head on the zone.

OK, thanks; problem must be downstream of the problem valve. Funny thing though; it sounds like water is rushing through the problem valve. I left the it (and the master) open for an hour and didn't see any sign of any leak...

OK...lets start at it from one end and work methodically through to the other.

Why not open the MV manually for a bit so that you know you have water flowing past it. Then, open the problem valve manually. Do you have water?
_____YES: then the problem is either the master valve or the problem valve. Close the problem valve and open it using the controller. Do you have water?
____________YES: Then it seems that the MV isn't working properly
____________NO: Then the problem valve isn't operation correctly

_____NO: remove the solenoid from the problem valve. Do you have water spraying up?
____________YES: The problem is downstream of the problem valve, a pinched or plugged line.
____________NO: The problem is upstream of the valve. Most likely the MV.


Hope this helps

But as I said, I replaced the solenoid, verified that it works, and replaced all of the parts in the valve (including the diaphram - I actually tried three different sets of parts including brand new ones). Not a drop comes out of the sprinkler heads, so it's doubtful a line is being pinched. I have no ideas about what to try next.

That is pretty unlikely for it to do that. I would suspect like Wetboots said that the MV is only hampering your efforts to diagnose the problem. I would suspect your problem is further down stream. Try troubleshooting the actual non working zone valve at this point. IE - the diaphragm and the solenoid for starters.

But is it possible that the master valve fails to work properly <i>only</i> when my problem valve is activated?

The master valve isn't the problem. It just interferes with your attempts to diagnose the original valve problem.

I do have one, but if there was a problem with it, wouldn't every other valve be affected?

A master valve is installed before your zone valves and after your backflow device. Basically, it is in place to keep water from flowing to your zone valves. If there is a leak downstream from the master valve, it won't leak constantly when the water is off. The master valve opens when a zone valve opens, thus allowing water to flow out to the system. Like I said, you will know if you have one if a wire is connected to the MV terminal on your controller.

What does the master valve do basically? I wouldn't know how to begin to troubleshoot...