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DrRon

New Member

Posts: 4

Location: Denver

1

Tuesday, November 30th 2021, 1:38pm

Zone Leak

I have one zone in my 20 year old system that seems to have an underground leak.

The line from the manifold valve is 3/4 inch PVC with 1/2 inch flexible feedlines to 5 individual pop up Toro 570 sprinklers.
2 or 3 heads won't pop up fully and 20 minutes of run time generates mushy sod half way into the zone.
I winterized the system with my 100 psi compressor and couldn't get full water blowout at the one uphill head.
I am in the process of replacing all the Toro 570 sprinkler guts with new parts to assure good seals and smooth popup surfaces. I'll replace all the nozzles with Toro MPR+ 10' VAN 360 Adjustable nozzles.

When I get everything replaced I can pressurize the zone with air but don't know if that will tell me if there is still a leak when I run water to it in the Spring. We seem to be having an endless summer here in Colorado...

Bottom line question is how do I find a leak in the zone line or connections without excavating my backyard lawn? :huh:
I guess I can excavate around each head first to look for leaks when I replace the inner parts as well as assure tight fit on the risers. Do I then slice sod back along the feedlines checking for leaks at connections to the main line?

My other thought is to excavate up from the mushy area to the mainline and search left and right from there.

What professional tricks am I missing to solve this mystery?

Thanks
If it ain't broke, just wait.

mrfixit

Moderator

Posts: 2,573

Location: USA

2

Tuesday, November 30th 2021, 11:02pm

That leak should be easy to find. It's near the mushy area. You could turn off all the nozzles with a screwdriver. Watch for the flooding. Maybe let the ground dry up for a day first.
I find it easier to turn the nozzles off while the sprinklers are running. Then again, I don't mind getting wet.

DrRon

New Member

Posts: 4

Location: Denver

3

Thursday, December 2nd 2021, 12:22pm

Zone Leak

OK, good idea to shut off the nozzles in the zone.
I'll be using the TVAN 10 Adjustables and they look like leaving them closed should limit their flow to a dribble, right?
Doing this procedure in the Spring right at system startup should have really dry ground to work with.
So a break or loose connection should show up well.
I can set the controller to run the zone manually one minute at a time until the leak shows up.
Then it's a matter of sod surgery...
Got any recommendations for a good sod scalpel?
If it ain't broke, just wait.

DrRon

New Member

Posts: 4

Location: Denver

4

Monday, December 6th 2021, 1:55pm

Zone Leak

https://photos.app.goo.gl/EZahe3RAnDW6zac89

Well, good news and bad news.
I dug up the sod and found the leak.
Good news is it wasn't a broken PVC line.
Bad news is it was a failed auto drain valve (old age).
Please look at the picture showing the multiple system lines with the leaking zone at the bottom.
I decided to replace the drain valve with a brass plug to eliminate any further moving parts issues.
But I am just wondering if the next year I winterize the system enough water will be trapped in the fitting to cause a problem with freezing expansion?
I can hit the line with 100 psi several times but will there be enough water trapped in the plug fitting to cause a freeze failure?
Thanks... ?(
If it ain't broke, just wait.

Wet_Boots

Supreme Member

Posts: 5,379

Location: Metro NYC

5

Wednesday, December 8th 2021, 9:03am

100 psi isn't needed for winterizing. That practice was a relic of days using an air hose for the job. What should be done is to adapt the compressor outlet to a garden hose thread, and to use a quality garden hose for the winterizing. Then the pressure can be adjusted to 60-70 psi. The zones will blow out better without any restrictions to airflow. 100 psi in zones can destroy sprinkler heads.

As for the drain valve, go ahead and replace it with a plug, so long as you are winterizing with air.

As for nozzles, you are better off with fixed arcs, since VANs are subject to adjustment drift.

DrRon

New Member

Posts: 4

Location: Denver

6

Monday, December 13th 2021, 9:57am

Zone Leak

OK, I understand old school compressor issue.
I'll be more careful limiting the tank pressure.

And I believe I can adapt my compressor output line to a garden hose configuration.
But how in the world do I connect the garden hose to my backflow valve?
I'm currently using the upstream test port with my air hose quick connect fitting.
Do I jury rig that test port from the quick connect to garden hose somehow?
Seems like I need to do the same as from the tank to garden hose in reverse.
My plumbing is 1" copper from the basement to backflow valve and from backflow to manifold PVC.
Thanks for the help...
If it ain't broke, just wait.

Wet_Boots

Supreme Member

Posts: 5,379

Location: Metro NYC

7

Monday, December 20th 2021, 4:32pm

You should have a garden hose thread air inlet on the system plumbing for the winterizing. That gets the job done quicker, and with less air pressure required. Using the backflow preventer for an air input is not optimal.

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