Valve Sticking Open

Another very common maintenance task or irrigation problem that I run into is a valve that is stuck open or in other words, a valve that won't shut down. A valve is a mechanical part that opens and closes every time that particular zone or section is used. over time the diaphragm wears down and will stick open, stick shut, or stick partially open.

This will of course affect the pressure on every other zone on the system because it is still constantly demanding water while the other zones are trying to run. On a pressurized system such as a city water source or a pump with pressure tank, the main water source will have to be shut off to get the valve to turn off or else it will not stop running. On a system with a pump and pump start relay, the valve will run while the pump is running.

This problem is caused just by normal wear & tear, or well debris such as iron accumulating in the valve over time causing it to clog and stick. This problem can be fixed by replacing the entire valve, or an easier method is to get a repair kit with replacement diaphragm for the same model and size valve. Many times the valves are an odd brand that is hard to find or a dis-continued model and in this case you will have to dig up and replace the entire valve.

If you can locate a repair-kit for that particular model valve, it is usually pretty simple. Just make sure the water supply is off, dig out enough under the valve to let water drain and not let dirt flow back in the system, and then remove the screws are bolts holding together the top and bottom half of the valve. You simple remove the top halve, remove the old diaphragm and screw the bonnet (top of valve) back on. Remember, it is very important to not let dirt get in the system if you don't want to deal with other stuck valves and clogged sprinkler heads. I always have a hand pump ready in the valve box hole ready to get all the water out so that I can make the repair nice and clean.

Instead of just using a repair-kit with replacement diaphragm, I use a brand new valve and remove the entire top, including solenoid. The reason for this is because it will save you time in the future. If the valve is old enough where it is sticking open, staying on, and not shutting off, then soon enough the electric solenoid will go out. So, I just use the whole top of a new valve. The only extra step is removing the two wires on the sprinkler multi-strand from the old solenoid to the new solenoid.

Scott
http://www.autolawnsprinklers.com

Rotor Head vs Spray Head

A common question that I get asked is: "What is the main differences between a rotor head and a spray head?" Well, there are a couple of main differences between these two types of sprinkler heads that I will define for you. Neither type is superior over the other, they both have their pros and cons, it is just that each is suited better for a particular types of applications, which I will share with you now.

A spray head does not rotate or turn and will apply water approximately 3 times faster than a rotor head. Sprays come in a variety of nozzle patterns and distances commonly ranging from four to fifteen feet (there are 18 foot VAN nozzles available). The pattern come in fixed 1/4, 1/2, 3/4, of full circle 360 degrees.

There are also adjustable nozzles such as Rain Bird's VAN (variable arc nozzle) which can be adjusted from zero to 360 degrees. VAN nozzles are great for curves and certain areas, but they do use more water than a fixed nozzle adjusted to the same pattern and they do not appear to have as good or defined spray pattern. Spray heads have smaller, finer nozzles which do tend to get clogged easier. Sprays are great for smaller lawn areas, gardens, and shrubs.

Rotor heads turn or rotate, hence the name. A typical residential rotor throws an average of thirty feet. A range of 22 to 40 feet is common depending on pressure and adjustment of head. Rotor nozzles normally come with the option of one gallon to six gallon per minute nozzles. 1.5, 2.0 and 3.0 are the most commonly used nozzle sizes on residential landscape irrigation application.

Rotor have a larger nozzle opening and do not get clogged as easy as spray heads. You can use less heads and water the same amount of area with rotors compared to sprays. However, since they do rotate, they have a much lower precipitation rate than sprays, so they take about three times as long to water the same area compared to sprays. Rotors are great for larger lawn areas.

In a properly designed irrigation systems, both rotors and sprays will be used in the most appropriate places. A smart irrigation designer can determine where each type of head will be most beneficial. Also, it is not a good idea to mix rotors and sprays on the same zone (although I see it quite often while doing maintenance) because of there different precipitation rate. There are certain circumstances where rotors and sprays can be mixed and be beneficial to the landscape design, but this is left to the most advanced irrigation specialists (like myself of course) who fully understand irrigation system dynamics as well as landscape, lawns, plants, flowers, and shrubs watering needs.

Scott
http://www.autolawnsprinklers.com