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jfotsch

New Member

Posts: 2

Location: Las vegas Nevada

1

Friday, November 28th 2014, 10:41pm

Multiple zones coming on at once

I am aware that this is an old thread and I have read over the material. I have a problem with several of my zones coming on together! I have 7 zones on 2 separate manifolds. Manifolds are fed by a single brass anti-siphon with 3/4" pvc ball valves in front of each for repair work. I reworked this 40 year old system about 8 years ago and changed all of the valves and solenoids and pop-ups. I used to be a plumber by trade (now am a union electrician) so my manifolds are much prettier than the originals and are 18" below grade. The problem started about a month ago when I heard a zone surging/pulsing; causing a brass head I have to be rather loud and got my attention. I assumed it was a solenoid so I changed it out. Then while I was testing the system I noticed that zone 7 was coming on with 3 other zones with the controller. I changed out several other solenoids without change and assumed it was the controller. I had only had that controller in the system for about 5 years, but changed it out anyway. The first was a 6 zone rainbird that was on the wall in the garage; lasted 25+ years. The second was a rain-go 9 zone (HRC-100C) with a rain-tight enclosure that I installed outside so it is accessible without opening the garage. The new one is a orbit 57900 (12 station) that is identical to the rain-go. In fact as I was installing I noticed that 100% of the parts are interchangeable. I wanted another but water restrictions caused me to go with this one. The same problem. Zone 7 comes on only with zones 1, 5 and 6. I manually opened the valves and number 7 keeps coming on even when not under the controller voltage to actuate the solenoid. Why would that zone not come on with any of the others? Zone 1 is in another manifold 60 feet away. The valves always shut down quickly after a cycle. The system has not been opened or touched nor has any of the plumbing on the property been accessed. The valves are 3/4" orbit model 57100's "made in usa". Could it be possible that the diaphragm in the #7 valve needs to be changed or is it more likely that some debris or slug/bug/sand got in there? When I first started reworking the original system (before building new manifolds due to finding matching valve parts problem) I only got lucky a couple of times changing out parts. Should I use a pool/spa lube on the o-ring? I only purchased one extra valve when I rebuilt the system. Are those diaphragms available still?
Any help would be much appreciated. Before I go opening up the valves I could use some professional support! ;(
Thanks,
Chris

Wet_Boots

Supreme Member

Posts: 5,248

Location: Metro NYC

2

Saturday, November 29th 2014, 11:34am

A "surging" zone bespeaks of a restriction somewhere upstream. Even without upstream restrictions like a partially-closed valve, a poor design can create the condition that encourages this 'surging' which is easily felt like a rhythmic hammering beneath your feet. The simplest possible for surging, once the upstream plumbing is ruled out (and downstream plumbing, too, since a break in the zone will increase flow and maybe start the surging) is to try a new diaphragm in the zone valve. Also, if the zone valves have flow controls (I bet they don't) you can try throttling them down, to see if that alone can stop the surging.

A stuck-open valve can also indicate the need for a new diaphragm. You can always disconnect a solenoid wire on a stuck-open valve, if you feel a need to rule out an electrical cause (the problem is almost always a mechanical one)

Orbit does sell parts, although pros do not generally try to find Orbit valve parts, instead choosing to replace the home center purchases with products with decades of reliable performance in systems. Consider an Irritrol 2500TF for a valve replacement.

jfotsch

New Member

Posts: 2

Location: Las vegas Nevada

3

Saturday, November 29th 2014, 5:53pm

I want to thank you for your more-than-adequate and professional reply to my questions. I was able to find the problem. The zone/valve that was coming on with several other zones had a small root growing into it. I had cleaned that set of valves off and dug around each of them gently and spraying/brushing them down to get a good visual and somehow did not see that a tree from about 25 feet away had gotten into that valve. When I rebuilt that manifold I did not leave much space between the soil and the bottom of the valves; hence a sneaky root compromised my system. I have now dug down and placed pea gravel and sand to keep this from happening again.
I had to sacrifice the guts out of the one extra valve I had from the original install because the diaphragm had been compromised by the root.
I also wish I had considered using commercial grade equipment when doing the initial install. I go better grade with everything else; just did not know that the differences were there. The nursery I use for fertilizers and fittings does not have any higher grade than rain bird on the shelf. It just did not make sense to me that the valve was not constantly running if it had been compromised. Learned something today!
Once again, thank you very much for your quick reply. I had a suspicion it was in the valves, but I was just hoping I would not have to use my "back-up" valve and might get a few more years before any maintenance.

Sincerely,
Chris

Wet_Boots

Supreme Member

Posts: 5,248

Location: Metro NYC

4

Sunday, November 30th 2014, 9:51am

I'm glad a new diaphragm worked for you. Keep an eye out for more of those valves, so you always have at least one on hand to get parts from.

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