Question
QUESTION: I live in TX and have city water (no well).  Although my water pressure is not great, the sprinklers work OK.  I  starting having problems with my system this weekend (it had been working since April).  When the sprinklers come on, I have a zone that starts watering, runs for a few minutes and shuts down.  I look at the controller and it still says the zone is running, a few minutes (or seconds) later the zone comes back on and does the same thing.  It switches to the next zone and then that zone just starts pulsating, the water is running but only every couple seconds is there enough pressure to pop the heads up for a split second.  I've looked for obvious leaks or a head that popped off somewhere, but have found nothing.  
I'm wondering if I have a solenoid going or if my wiring has been compromised.
Any advice would be appreciated.


ANSWER: That's a strange one.
The first thing I would do is find the valves and turn one on manually. (not by the controller) This will atleast establish if it's water or electric problems.
Next I would buy a pressure gauge and attach it to a faucet so you can watch it will the sprinklers are running. Check pressure without the sprinklers on (static pressure). Then run the system and watch. It should drop then stabilize and remain somewhat steady.
If you could do these things and reply back with the results it will give me a direction to help you. There are so many variables right now.

Matt

---------- FOLLOW-UP ----------

QUESTION: Thanks Matt.
Ran further diagnostics this weekend.  Running the entire cycle, the system went through the first 2 zones fine, then hit the 3rd and it did not come on.  The 4th & 5th zones did not work either.
I then re-programmed to skip zone #3, and then zones 1&2 and 4-6 all worked, but when it hit zone 7, again it and subsequent zones did not come one.  
I then took zone #7 out as well, but then none came on, so not sure what happened there.  It looks like zones 3 & 7 are the problem ones, but #3 is in the front and #7 is in the back, so I'm really confused now.  
Based on the test I ran, I don't think it is a h2o pressure issue, as the working zones seemed to do fine.

Also, looed at the valve briefly.  There is a screw on top with a Phillips head.  Is that a pressure bleed or is that what I turn to manually turn on the valve?  If not, how do I turn the valve on?

Thanks

ANSWER: This is a tough one.
First. The valve can be turned on manually by turning the solenoid CCW. Usually only 1/4 to 1/2 turn. Be careful not to turn too many times as the solenoid will come out. If you can give me the model # of the valve I can tell you exactly how to use the manual feature. The screw on the top is probably a flow control. You can turn it CCW about 1 turn and try the controller again.
I think for diagnosis reasons. You need to disconnect the #3 wire from the terminal at the controller. Now put time on the #3 zone and run through the system. If it works 1-6 without problems, (obviously #3 won't work) then I would say the solenoid on #3 is bad. What I believe it is doing is, sensing the bad #3 solenoid and shutting-off the power output to the rest of the valves. Some controllers have an internal "auto reset" circuit breaker. The same would be true for the unusual operation of the #7 valve.
Try these thing and get back to me.

Matt

---------- FOLLOW-UP ----------

QUESTION: It's an Irritrol 205S.

Does each zone have its own solenoid?  I didn't walk around the entire yard, but noticed only 3 in the front yard where there are 6 zones running.

Answer
Sorry for the delay of answering.
Yes, each zone has it's own valve and each valve has it's own solenoid.
It is possible the grass has grown over the ones in the back yard. look for a depression in the soil and use a screw driver to poke into the soil. You may be lucky and hit the valve boxes.

Matt