System Keeps Running & Won't Stop

We get a lot of maintenance calls to our office throughout the year. There are several different parts to an automatic irrigation system and thus there are many kinds of problems that can happen and cause a sprinkler system to not work properly. A common call that we get and problem that we have to diagnose and deal with is where a lawn/landscape sprinkler system will not shut down. A particular zone is stuck running and it won't shut off no matter what you have tried.

First of all, there is not one straight answer for all situations, but luckily there are a few main ones that cover most situations. You must first determine whether the problem is electrical or mechanical. To do this, go to the main power supply and turn off the circuit breaker that the timer is on, or unplug it from the wall if it is an indoor timer wired this way.

Simply turning the timer to "off" is not always sufficient, because many electrical problems that I've seen that are showing this symptom will keep doing it even if the timer is set to "off". Once you've cut the main power to the timer, the sprinklers will either go down or stay up. If they go down, then you know there is a problem with your timer. If the sprinklers are still stuck on, then you've got a mechanical problem.

The most common mechanical cause of this problem is a valve sticking open on a pressurized system. A pressurized system is one that is connected to a pressurized water source such as city water, reclaim water, or a pump/well system with a pressure tank. You can exclude systems with pump start relays from this unless it is the relay that is sticking, but you should have already ruled this out by cutting the main power supply to the timer & relay.

If you have determined your problem to be the valve, then you will need to shut the main water supply of and repair or replace the valve on the zone that is having the problem. You may be able to find a valve repair kit which includes the diaphragm. Many electric irrigation valves have screws or bolts on top that can easily be removed. Once the screws or bolts are loosened and taken out, you can lift the top part of the valve up and remove the diaphragm. If you are dealing with an older model or generic brand valve, you may have to dig a pit or hole, cut the PVC, and replace the entire valve. Good luck and as always you may contact me via email if you have any questions.

Scott
http://www.autolawnsprinklers.com

Replace Electric Valve

An irrigation system is similar to an automobile in the fact that it has many separate moving mechanical parts that all work together to help produce the end result. A very common and important part that can go bad are the electric valves. There is one valve for each zone or section of your sprinkler system and when one goes bad you will have to replace it.

Like an automobile requires maintenance, so does an irrigation system. It's funny because I'll run into people who are upset at having to spend $135 to replace a twenty year old valve, but they'll buy a new car every two or three years...go figure? There is not much you can do to prevent the valves from going bad, they just wear out. The first thing that usually goes is the solenoid, which can usually be replaced without having to remove the entire valve. You can find replacement solenoids for all of the major brands at your local irrigation distributor, Ace Hardware, Home Depot, or similar store.

Replacing the solenoid is fairly easy once you have located the right valve and diagnosed the problem correctly. The solenoid is on the top of the valve with two wires coming out of it. If you are on a pressurized water system such as city water, reclaim (recycled waste water), or pressure tank setup, then make sure to shut off the water source prior to replacing the solenoid. Make sure to clear the valve of all dirt and debris around and underneath it. Give some room for residual water in the line to run out. You may need to use a small hand pump or just a small cup to bail water out of the valve box. This is important so that you do not get any dirt or debris in the solenoid spot, which could cause the solenoid to not sit in the valve correctly and the valve could become stuck open.

When ready, simply turn the solenoid counter-clockwise until it is removed from the valve. Have the replacement in hand and ready to immediately install. Put the new solenoid in place and turn clockwise gently until it is snug. Be careful here because you can actually over-tighten the solenoid. An over-tight solenoid can strip the valve permanently damaging it and cause it to remain open. Too loose and the valve will stay on also. After you have installed the new solenoid, you are ready to wire it.

Now one at a time, cut one wire from the old solenoid and connect one wire from the new one. Then clip the second wire from the old solenoid and connect the second from the new one. It doesn't matter which wire goes to which, as long as one lead is on the common or negative wire (usually white), and the other wire is connected to the hot wire.

The next common thing to go bad is the valve's diaphragm. This is a rubber piece with a spring which controls the opening and closing of the valve. Their are only two things that can happen when the diaphragm goes bad: The valve is stuck shut and will not open, or the diaphragm is stuck open and the valve will not shut down completely or at all. As with solenoids, you can find replacement diaphragms for all the major brands.

In certain situations, you will have replace the whole valve by digging it up and cutting the PVC. I usually have to do this when I run into an older model electric valve that I cannot obtain replacement parts for. Another reason to have to replace the whole valve is when the valve body is actually cracked or damage for whatever reason. Most of the time you can replace just the bad valve, but if the valves were plumbed in too closely together you may have to replace more than one. I have had jobs where there is only 1 valve bad, but I had to replace six valves because whoever installed it plumbed them so close together, that it was impossible to only replace one. Usually this is better for the customer anyway, because once one goes bad, it is only a matter of time before the other ones start going bad.

The actual plumbing may vary from situation to situation, but the main points are to get the flow of the valve correctly. All reputable brand valves have an arrow on them showing you which direction that the water flows through them. All you have to do is to make sure that the valve is installed correctly by having the water flow in from the mainline out to the sprinkler heads. Replacing a valve is usually not that difficult, but can be a little time consuming. If you are ever in doubt, call a professional.

Scott
http://www.autolawnsprinklers.com