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Model SL800 controller, 5 zones, house built 2010, I am 2nd owner and no record of who/when/where/what installed.

Sprinkler stopped working after 3 years and program test indicated shorts on all valves. I did the "output" test, the MV was drawing 575ma, the 5 zones were each drawing 200-250ma, all within tolerance except the MV was high. I noticed that the sprinklers worked perfectly during the "output" test. I disconnected the wire to the MV and sure enough, the system started working fine, all 5 zones.

The MV is stuck open. Fortunately, it is stuck open and not closed. I am guessing the MV is defective and drawing too much power making the zones look like they are shorted.

The water meter connects directly to a pressure reducer. It was replaced due to the water pressure being too high. About 15 homes in this neighborhood, some built less than 2 years ago, had the same problem and needed a higher rated pressure reducer. Maybe this caused the MV to stick open?

At the water meter i can see the pressure reducer. About 36 inches away and off to one side is a back flow device. I do not know who the builder or first owner contacted with so I am on my own to figure out where the MV is. It is buried deep and the ground is hard to dig.

Would the MV be between the pressure reducer and the back flow device?
Would it be on the back side of the back flow?

If I know where to dig it would really be helpful.


I had a plumber out a year ago and he had trouble locating valves for me because there was too much electrical signals in the ground for his listening device to work. He did located one and I found the other nearby but we never looked for a master valve as I did not know there was one at the time. I called him because I was mapping out the zones and had found only 3 valves and knew there were 2 more somewhere. He also replaced the pressure reducer with a commercial grade one.

After a few water cycles the master valve closed all on its own. I attached / removed the MV wiring several times and managed to get it to stick open. I can hear a noise in the front so I or the plumber should be able to located it.

It needs to be replaced and I like your idea of just using a manual valve. When I bought the house I added an hose bib outlet in zone 1 as I didn't know the MV was stuck open. I verified it no longer works with the valve closed. I need that outlet as it drives two motion detector sprinklers to keep feral hogsout of my front yard.

The transformer, rated at 750ma, overheats badly. Looking at the TEST-OUTPUTS I read between 400ma to 975ma on the MV. Way to high. the 5 zones show 220 +/- 10ma each which is correct. I can put a resistive load on the output for the MV to fool the SmartLine controller but will have to add a 2nd transformer, 24vac, rated at 1amp to get the valve to close.