Sprinkler fuses keep blowing…

Lazy reference for sprinkler troubleshooting after my fuses kept blowing.

If your sprinkler system keeps blowing a fuse, look for the zone that gets no water. That’s where the short is. This document explains how to repair it.

If it’s not dead-grass yet, then make sure you are stocked up on fuses, and manually cycle through the zones. When you find the one that blows the fuse, replace the fuse, and set that zone to zero minutes. Test the rest of your zones.

Once you know which zone(s) are bad, you can run the system with the faulty zone disabled until you’re ready to replace the valve. At this point, you can call for help, or try to fix it yourself.

If it’s “all zones after zone X”, then you may have a cut in the control wire. You may need a metal detector to follow/find the wire unless you know where digging happened.

To locate your zones, you’ll need to know which color wire is for the failing zone. Look where the wires connect in your unit, and you’ll see numbers next to the wires. Black is common to all zones, and the colors are specific to the zones. The slot or screw for the zone should be numbered. In this example, we’ll say “Zone 3″ and it’s the Yellow wire here. Yours may be different.

If it’s just one sprinkler, find your failing sprinkler can in the yard. It should be a green lid, or maybe a whole cluster of valves in a box, or just next to the house or in a flower bed. The valve is green or black, maybe faded, with a hexagon sticking out of the top (solenoid). There will be waterproof wire-nuts or splices in there. These may be wrapped in tape, but inside, it should be grease-filled clips or wire nuts. If it’s not grease filled, that may be your whole issue, with corroded wires, etc. All of the valves will splice the black wire, but only one will splice the wire you identified before (Yellow for me).

Once found, look for any damage, but likely, it will just look normal, or maybe leaking water. Make note of the type of valve. Either it has 6 screws around the top (normal), or it looks like the whole cap screws off (jar top). If it’s anything else, you may need help from a professional to replace the entire valve body, splice pipe, etc.

When you go to replace the solenoid, it’s better to just replace the entire top part. Likely, the valve gasket has aged, etc. It’s often lower cost than buying the valve kit plus the solenoid. Just buy a whole, new 3/4″ or 1” valve. It does not matter which of the 2 sizes you get, since the top half is the same for both. The only thing that matters is if you use jar-top or normal top.

Also, buy waterproof splices or wire nuts, and more fuses. They are usually 1A fast blow, glass tube (GMA1), though some are 0.5A and some are 1.5A. Check your book to make sure you get the right ones, but Rainbird ESP is 1A.

When you’re ready to replace the valve, turn off the system so there is no chance of it turning on while you’re working. There should just be an “off” position, but you can unplug the power brick too if you want. It’s only 24 volts, but it’s AC, and the box will have water in it. This makes it a little bit of a hazard, at least from a comfort issue, if it were to turn on.

Next, turn off the water. The sprinkler system is under constant pressure, and the valve just lets the water into that loop or leg. It’s really tough to replace while it’s flowing. If you don’t know where the shutoff is for your sprinklers, just turn it off for your whole house at the street. This usually takes a wide-slot t-bar tool, but you can hammer a 1.5″ steel pipe partially flat on one end and use a pipe-wrench if you really need to, and have that handy.

If there is no shut-off for your sprinklers, then now might be a good time to install one. You’ll need pipe cutters, a shovel, a lawn box for it to go into, pipe cement, and a valve (ball valve is best). Go with something that has a hefty handle so it won’t need replacing later.

If you wanted to drain the pipe, you can open a valve by twisting the solenoid counterclockwise 1/8th of a turn. That will let the pressure out of the pipe and it will drizzle into whatever sprinklers are there. If the valve is at the low spot, you’ll still have water come out when you pull the valve. That’s fine, because it will help flush some of the debris out of the valve (if any).

Remove the clips/wire nuts, and push the wires aside. You don’t need to pay attention to polarity. It’s 26 volts AC, so it’ll work no matter which way it’s wired. If you’re geeky, you can check resistance, and it should be in the 25 Ohm range. Too low is a short, and too high is corrosion inside. Jus tmake sure that you don’t lose any of the black wires if there are several clipped in.

Next, remove the 6 screws from the top of the valve, or unscrew the cap if it’s a jar-top. If it’s too stuck, an oil filter wrench, or robo-grip, or channel locks can help. There is a spring that may want to leap out, so be careful removing the very top. Collect all of your parts. You should be left with just a plastic housing mounted in the pipe that has some concentric rings inside, but no loose parts.

If any dirt clods or crud has fallen in there, pull it out, rinse it out, or turn on the water part way to flush it out. it does not have to be spotless, but it should not be muddy.

Pull the top off of your new valve, and swap it in place of the old one. If you’re doing multiples, or decided to replace them all (they have a life-span of about 15 years, so it’s just a matter of time…), then do them.

Once it’s assembled water-tight, turn on the water supply and look for leaks. Solenoid should be snug clockwise, any bleed screw on the top should be snug, and etc. The sprinklers should not be leaking. You should not hear water flowing.

Next, test that it turns on manually by twisting the solenoid counter-cockwise about 1/8th turn. The sprinklers should come on. Twist it back to shut them off.

Once you are sure it’s water-tight and works properly, then connect up your wires with grease caps. It does not matter which solenoid wire goes to which control wire, but any common/black splices in the main cable need to be preserved. If your grease caps are the small, screw on kind, then you’ll want to wrap them in hurricane tape or gaffer’s tape to keep them clean. The snap-shut caps are ok to be left loose in the can.

If you need to replace the can, then now is a good time. You may have to cut out the bottom of the pipe-hole to fit it over. It’s a pain to dig out, but if it’s messed up, it will protect your new valve better to have the can replaced. Just don’t shovel into your control wire. The 7″ round cans are good for one valve, but if you have all of the valves together, a bigger, square/rectangle box may be needed. Even if it’s all above ground, keeping them boxed will keep animals from nibbling on wires.

Now, the moment of truth, test from the controller. Make sure you can manually enable the repaired zone(s). If not, check your wires, since you should have already verified the valve manually works. If anything fails, go back and re-do the steps. Maybe you dropped the spring, or forgot to put the valve gasket in?

If you’re stuck, and it’s bad, then this might have been a project to call a professional about. Maybe you can get someone quickly. Turn off the water if needed.