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skintdigit

Unregistered

1

Monday, June 11th 2012, 7:27pm

Homeowner wiring SNAFU, can you help sort it out?

Neighbor calls and says irrigation system worked fine last year, not working this season. So I run by for a look. He has replaced the timer(4 station), and replaced fence posts near where the control wiring goes around the foundation corner. There is an AVB near the foundation, but no pressure in the line there. Owner says he did not turn any valves off last year, and I was unable to locate a shutoff for the irrigation system out in the yard near the water meter, so if there is a valve box at the shutoff, it has not been opened for a long time. So, I break out the 521 locator, and trace/locate 2 valve boxes, neither with pressure at the valve(of course, because the AVB loop is dry, too). So now I'm thinking he's cut the control wiring with the fence post excavation and isolated a master zone valve and the other valves that I can't find. Next day, I run back with a shovel and gently dig up the wiring near the new fence post. Thank goodness, the owner did not encase them in concrete and there is a small nick or two, but the wires are continuous there. At that time, the owner tells me that he's not sure he wired the controller correctly when he installed it. Line wiring is correct, reading 29 VAC at the control terminals when a station is turned on. So I disconnect everything and ohm out the control wiring. Wire labeled #1 was on the common terminal, #2 on the the master(pump) terminal, and #3,4,5,6 were on zones 1 through 4. Here is my crude chart with the resistance readings:





Looks like he was correct about the wiring problem, #1 does not look like the common. What do you guys think is going on....shorted solenoid on #2 or #6 that might just happen to be the master valve solenoid? Looks to me like #2 or #6 should be the common, but both have low resistance across the page and the resistance across 2 and 6 is only 3 ohms.

Not sure what to do next, either break out the 521 again and hook up to #2 or #6 and try to locate the master again, or just start digging upstream from the AVB. Any ideas?

Skintdigit

Wet_Boots

Supreme Member

Posts: 4,064

Location: Metro NYC

2

Monday, June 11th 2012, 8:03pm

It isn't impossible that both 2 and 6 are common wires.

The value of making this sort of grid of measurements, is to look for the lower readings that point out the common wire. The lower readings show the resistance of a single solenoid. The higher readings show the resistance of two solenoids in series.

skintdigit

Unregistered

3

Monday, June 11th 2012, 9:51pm

I thought the same thing, Wetboots. So before I left I attached both 2 and 6 to the common terminals(there are two on this controller) and hooked the others to the zone terminals, then cycled through manually one by one....still no water to the AVB :( .

skintdigit

Wet_Boots

Supreme Member

Posts: 4,064

Location: Metro NYC

4

Tuesday, June 12th 2012, 4:52am

You can always work backwards by connecting a battery to the wires in the field, and checking the controller wiring for voltage

skintdigit

Unregistered

5

Thursday, June 28th 2012, 9:22pm

Wiring snafu

Wetboots, thanks for your thoughts on the wiring foul-up. Yesterday, I took a shovel and dug some more around the vicinity of the valves I had traced earlier...scraped off the lava rock and pulled back the plastic liner. Found the master and all four zone valves close together. Not quite a manifold arrangement, but they were close. Master valve was upstream of the AVB and had a very corroded solenoid. Manually turned on the master to verify flow to the AVB loop. Based on the low resistance readings above, I thought that wires #2 and #6 might be the master control and common. Cut the wires at the master and used a 9v. battery to verify. Sure enough, #2 was the common and #6 was the control wire for the master. Once I had the common and master verified, I just used trial and error to locate the remaining wires in their proper terminals on the timer. Had my son help listen for clicks at the solenoids. Still have a couple of valves that are sticking open, but the master is shutting off now and we'll get the others sorted out with new parts or a cleaning shortly. These are old Rainbird valves, round cover, roughly 4" in diameter on 1" pipe. Single thumbscrew on the top center with a bleeder in it and a metal rod attached....about 2 1/2 inches long. The wiring was all red, no white wire to identify common. I hope this thread might help someone else who might encounter a fried valve solenoid and fouled up wiring at the same time, as we did.


Thanks again, Wet Boots!

SD

Wet_Boots

Supreme Member

Posts: 4,064

Location: Metro NYC

6

Friday, June 29th 2012, 10:47am

You should complete the repair picture by replacing the atmospheric vacuum breaker with a genuine Pressure Vacuum Breaker.

skintdigit

Unregistered

7

Friday, June 29th 2012, 3:44pm

wiring snafu

OK, what is the benefit....reliability? Is that change something that usually requires permitting by a licensed irrigator?

SD

Central Irrigation

Supreme Member

Posts: 347

Location: Central Minnesota

8

Friday, June 29th 2012, 7:19pm

The benefit is keeping your and your neighbor's drinking water safe to drink. And, yes it should be done by a licensed professional.

Wet_Boots

Supreme Member

Posts: 4,064

Location: Metro NYC

9

Friday, June 29th 2012, 8:29pm

the preferred order of pieces in the water chain is PVB - master valve - zone valves, because it is best to have the PVB pressurized 24/7

skintdigit

Unregistered

10

Friday, June 29th 2012, 9:39pm

Thank you. The order of devices you've given makes sense. I was surprised to find the master zone valve upstream of the AVB, because it seems logical to have the cross-connection prevention device as the first device in the chain after the main system shut-off. My question was about the differences and advantages of a PVB over an AVB.

SD

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