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

Hi, I have recently installed a new drip irrigation system and am having some problems. The system is on a well that puts out 60 psi and about 6 gpm. The controller is a Rain Bird ISM-6, and the valves are 100-PGA valves, both are new. The wire is brand new 18/7, direct-bury wire. The water setup passes through a back-flow valve, a 50psi pressure regulator (that works under constant pressure), a 200 mesh basket filter, and then the six PGA valves. It is distributed by .75 in PVC pipe to Rain Bird XFD dripline and emitters in garden beds. The zones run for 3.5 hour lengths. I have the flow on the PGA valves turned down as recommended.

I can run the system manually with the ISM controller and I get no errors and the valves put out water, but when I let the automatic timer run, I see zone errors when I check it the next day. I have run the 'valve test' setting and all the zones work, but sometimes the solenoids make loud buzzing sounds when they come on, and sometimes they are quiet. I was told this may be a sign of low voltage, so I check the controller with a multimeter. The readings were 27 V for each zone, so I think the controller is OK. To double check, I switched the controller out with my ISM-9 controller, and I still got the same zone error codes. I also tested the resistance of the valve lines at the controller and got 39 to 40 ohms for each zone, which is within the specs I was told for the PGA valves. Rain Bird tech also told me that the ISM controller outputs more than enough amps to run these valves one at a time. I also ruled out the controller power since I have temporarily connected the controller to a UPS power supply that should be providing the controller clean and even power.

So, I am wondering what could be the problem and why am I getting these ERR codes on the ISM controller. The erratic loud buzzing of the solenoids also worries me, but I am not sure what the cause could be since it is not consistent and changes from sometimes loud to sometimes quiet on any of the valves (not all at once, and not consistent). This is a new installation and I just can't figure out what is going on.

Help! Thank you.

I have tried switching between my ISM-6 controller and my ISM-9 controller, and it made no difference. Or are you saying to try a different model/brand?

The wiring is close to perfect from what I can tell. It is wired up with brand new 18/7 underground cable and is connected with silicone filled connectors. I checked each run at the controller box and got 39-40 ohms for each zone. The white wire is a common ground for all valves and the colored wires are connected to separate valves. I can't see anything that could be wrong with the wiring.