John Deere Landscapes

Drip Irrigation Spacing

2006-05-04T11:04:00.000-07:00

Question:
I just installed a drip irrigation system in my garden area. I have tested it several times to make sure it’s working properly before I plant my flowers. I have set the timer for 30, 45, then 60 minutes to see if I can get the right coverage. The ground gets wet at a radius of 3 to 5 inches from each hole in the tubing. This is true no matter how long I run the system. Since the holes are spaced 12” apart and it’s not reaching the full 12” in each direction, I am getting frustrated.

What can I do to improve the coverage area?

Answer:
Please don't mistake what you see at the surface for the total wetted area. It is important to remember that each emitter "hole" creates an onion shaped wetting pattern underneath it. The onions meet under the surface (of the soil) to form a uniformly irrigated area. If you took a knife or screwdriver and probed the soil halfway between the emitters he would most likely encounter wet soil just below the surface. Thus, I would guess you are getting full coverage, it just doesn’t appear that way from the surface.

Circuit Breaker Size

2006-04-20T11:40:00.000-07:00

Question:
I am installing an irrigation lake pump at my house. It will probably be a 2 HP (Horsepower) pump. What size circuit breaker do I need?

Answer:
As usual, I can’t give an exact answer because it depends on several factors. Are you operating the Pump using 230 volts or 115 volts? What is the “service factor” on the pump motor (this will help with determine the true horsepower of the pump)? How sensitive of a breaker is being used? Etc.

However, I have a general guideline to follow. Read the Full Load Amps (FLA) on the pump motor plate. Most contractors install twice the FLA. Thus, if the pump draws 15 full load amps, the circuit breaker should be 30 Amps. Also, never go larger than three times the FLA. Thus the MAXIMUM size would be 45 amps.

Here is a general guideline of Full Load Amps (based upon 230 volts):

1/2 horsepower pump draws roughly 5 Amps (15 Amp breaker)
3/4 horsepower pump draws roughly 7 Amps (15 Amp breaker)
1 horsepower pump draws roughly 8 Amps (15 Amp breaker)
1 1/2 horsepower pump draws roughly 10 Amps (20 Amp breaker)
2 horsepower pump draws roughly 12 Amps (25 Amp breaker)

Please Note:
This is based upon 230-volts at the motor. 115-volts will double the Amperage draw.
Always read the motor FLA on the pump motor itself. This is a much more accurate number. Lastly, always have a licensed and qualified electrician do the installation according to your local codes and ordinances.

Sloping Drainage Pipe

2005-12-22T07:35:00.000-08:00

Question:
I am installing some drainage pipe at my house. The manufacture states to install the pipe on a 2% slope towards the outlet (or away from the house). How do I know if I have a 2% slope?

Answer:
How do we check to see if we have a 2% slope? One option is to take a level and tape it to a perfectly straight 10’ board. Place one end of the board on the ground (near the top of the slope), take the other end and raise it off the ground (near the bottom of the slope) until the board (& level) is perfectly level. Now measure the distance between the board and the ground at the bottom of slope. It should be 2.4” drop. (10'x 12" = 120" x 2% = 2.4") Thus, we have a 2% slope.

18-Gauge Wire & Valve Operation

2005-11-09T06:55:00.000-08:00

I am using Multi-Strand wire on a residential installation. The thickness of the wire is
“18- gauge”. How far can I run this wire to operate my valves?

Answer:
The distance depends on a lot of issues......

The voltage coming out of the transformer, 24 or 26 volts?
The size of the transformer or how many amps is the output?
How many valves are you operating at one time?
How many amps or watts does your solenoid draw? Type of solenoid?
How much water pressure is at the solenoid?
How good are the wire splices?
Etc.

These are all considerations that need to be taken into account when sizing valve wires. However, if you want a simple down-n-dirty answer, use this guideline.

18 Gauge is good for 1000 feet, if you are operating one valve at a time.
For two valves operating at a time, cut this number in half.
For three valves operating at a time, cut this number in thirds.
Etc.

Pleaae note: This is for new installations only with new solenoids.

Zone Won't Turn Off

2005-11-02T06:16:00.000-08:00

I have a situation where one of my irrigation zones won't turn off (even when I unplug the controller and take the batteries out of it). The only way I could get the water to shut off is to turn it off at the main water supply. Any help?

Also, I noticed that the valve box is filling with water. Is that normal?

Answer:
First, yes its normal for a valve box to fill with water, (unless you have a good draining soil like sand). Usually, a small drip will fill the valve box or rainwater will collect inside of it, thus filling it. I usually recommend having 12” of gravel underneath the valve box to drain any collecting water.

Since you unplugged the controller and the valve is still operating, that tells me that it’s not an electrical problem; it must be a hydraulic problem.

First check the obvious. There is a "manual bleed screw" on top of the valve. This might have come loose, thus keeping the valve operating and the valve box flooded. However if you did check this and its not the problem, than the valve has to be stuck in the open position, or the solenoid (on top of the valve) is not seating properly, thus keeping the valve on.

You essentially have to take apart the valve and remove the internal components. Wash them down with a hose and reassemble them. Visually check the diaphragm for small tears. Also, I would replace the solenoid with a new solenoid to make sure it seating properly. It has to be one (or both) of those problems. Lastly, check to see if the body of the valve is cracked, this would keep the zone operating too.

It might be cheaper to buy a whole new valve and swap the components. You can purchase at your nearest John Deere Landscapes store at 1-800-347-4272. A new 1" residential valve should cost roughly $20.

Pond Water Volume

2005-10-19T11:02:00.000-07:00

How do I calculate how much water is in my pond?
I am adding a water treatment to my pond and I need to know how many gallons of water is inside of it.

Answer:

First figure how many cubic feet are in the pond.
This is calculated by taking the average width x average depth x average length.

Thus, if your pond is roughly 10’ wide by 3’ deep by 10’ long,
our answer would be 10 x 3 x 10= 300 cubic feet.

Now, we have to convert to gallons.
There are 7.481 gallons in a cubic foot. Thus, 300 x 7.481=2,244 gallons of water.

Best Time of Day to Irrigate

2005-10-11T06:03:00.000-07:00

What is the best time of day to irrigate and for how long? I have rotary sprinklers for the grassy areas and small misters for the shrub areas. Someone told me that misters put out so much water that you do not run them as long as the large rotary sprinklers.

Answer:
I cannot give you an exact time in minutes to water, but here are some very general guidelines.

1. Irrigate early in the morning. Your "evaporation rate" is much lower compared to the hot mid-day sun, thus saving water. Don't irrigate at night, this promotes various turf diseases. Diseases love cool nighttime temperatures.

2. Misters (actually called Spray heads) do apply more water then rotors. Rotors generally apply 1/3" of an inch of water per hour compared to Misters applying about 1-1/2" of water per hour. Thus a 1 to 5 ratio (Misters versus Rotors) in "run-time" is a very general rule.

3. Grassy areas need more water than your shrubs.

4. Here is a link that might help in your research. www.Irrigation.org.
There is a lot of additional links on their website.

Zone on a Hill

2005-10-10T13:47:00.000-07:00

One of my zones runs up an 8-foot high hill. When the zone is finished operating, all the remaining water in that zone runs out of the lowest sprinkler head (at the bottom of the hill). This creates a large puddle. What can I do to fix?

Answer:
In the lower sprinkler heads, you would have to upgrade the sprinkler with a "Sam" feature.

A Sam feature stands for "Seal-A-Matic". This type of sprinkler would have a check valve in it to prevent the "low sprinkler head drainage".You can call 1-800-347-4272 for you’re nearest John Deere Landscapes store, they will have these sprinklers in stock.

Check for A Leak

2005-10-07T05:29:00.000-07:00

I suspect that I might have a leak in the sprinkler system (my water bills have doubled in the past couple of months). Is there an easy way to check if I have a leak?

Answer:
Shut off all the faucets inside the house. Make sure you verify everything is off and no water is in use. Now, without any water running in the house and the irrigation system off, check your water meter.

If your water meter odometer is standing still, then everything is ok. If your water meter odometer is moving, then there is a leak somewhere.

PSI & Pipe Selection

2005-10-06T07:51:00.000-07:00

I am working at a job site that has 55 PSI. What product is acceptable to use, the 200 PSI rated pipe or 160 PSI rated pipe?

The selection of PVC pipe with the proper pressure rating is an important consideration. Typically, the designer determines the normal working pressure range of the irrigation system, adds on an appropriate safety factor for expected surges, and selects a pipe that is rated at this pressure (or at a higher pressure).
The pressure rating for 200# pipe and 160# pipe is listed below. As you may notice, the 160# pipe is more than capable of handling pressures in your scenario.

Class 200 PVC Pipe.……..
200# working pressure rating
420# sustained pressure rating
630# burst pressure rating

Class 160 PVC Pipe.……...
160# working pressure rating
340# sustained pressure rating
500# burst pressure rating

Question: Why is it designers specify 200 PSI pipe, if 160 PSI is more than capable?

The reason for this varies depending on the designer. It can be something as simple as “what is more readily available” or “just not knowing the pressure at the site”. This could encourage the designer to choose the higher rating.
However, I would guess (more times than not), the real reason is being fearful of a “less than perfect installation conditions”. Simply put, there is more margin for error on the “installation” side as opposed to the “pressure capacity” side. Any time the pipe is pulled against a rocky soil (which can scrape the pipe thus weakening it) or too much glue is used (which potentially weakens the pipe) or the trench is backfilled with rocks as opposed to sand, are all reasons for specifying a higher-class pipe. If we have a installer that understands the importance of properly handling, gluing & installation of PVC pipe, the lower pressure rating will work fine for you scenario.

45-degree Angle for Ball Valves

2005-10-04T08:56:00.000-07:00

Somebody told me to leave the ball valves on my backflow preventer at a 45-degree angle (or the half open-half closed position). Why?

Answer:
In the normal operation mode, they should be fully open. However, after the system has been winterized the ball valves on the backflow preventer are supposed to be at a 45-degree angle.

In the winter months (when the system is not in use and has been winterized) condensation can be trapped in a fully open or fully closed valve. This usually occurs between the ball and the body of the valve. In freezing temperatures the water will freeze, thus cracking the valve.

Again, only in the winter months after the system has been winterized should the ball valves be left at a 45-degree angle.

Pump with Pressure Switch

2005-09-27T11:34:00.000-07:00

I want to use a pressure switch to turn on and off my irrigation pump. What pressure switch should I use?

Answer:
It all depends on……
What pressure do you want the pump to turn-on at &
What pressure do you want the pump to turn-off at?

The most common and inexpensive pressure switch on the market is the “Square D” type. Below are the various modes for the various pressure settings.

On 20-Off 40 psi # 9013 FSG2 J20 standard switch
On 30-Off 50 psi # 9013 FSG2 J21 standard switch
On 40-Off 60 psi # 9013 FSG2 J24 standard switch
On 50-Off 70 psi # 9013 FYG2 J33 medium duty switch
On 60-Off 80 psi # 9013 FYG2 J25 medium duty switch

One word of caution: Don’t play with the pressure adjustments, unless you’re a qualified professional. The adjustments are very easy to mess-up, thus potentially damaging your pump.

Winterizing

2005-09-26T13:42:00.000-07:00

Had a customer ask about winterizing their irrigation system today. I refered them to the article I posted previously and to the manufacturers links below.

http://www.hunterindustries.com/Resources/Technical_Bulletins/winterization.html

http://www.rainbird.com/diy/support/itg/Winter/index.htm

Sizing A Pump

2005-09-23T08:12:00.000-07:00

Here is an easy-to-understand explanation for sizing an irrigation pump.

In order to size a pump, you need to know two things.
How many Gallons Per Minute (GPM) you need &
How many Pounds Per Square Inch (PSI) you need.

For GPM, decide what zone will be your largest zone & how many sprinklers will be turning on at a time.
For Example, if your largest zone is 6 rotary type of sprinklers with a 3 GPM nozzle in each head, then your GPM would be
6 heads (times) 3 GPM (equals) 18 GPM needed.

For PSI, you typically need to know
How much pressure do you need at the sprinkler (plus) how much pressure will you lose through friction loss.
For Example, a typical rotary sprinkler optimum working pressure is 40 PSI (plus) a typical friction loss might be 20 PSI...
Thus, 40 PSI (plus) 20 PSI (equals) 60 PSI needed.

Now, you can look in our catalog or call 1-800-347-4272 and ask for a pump to deliver 18GPM @ 60 PSI.

Winterization

2005-09-22T12:57:00.000-07:00

Had a question about winterization today. Specifically on what size compressor to use.

I E-mailed the customer the article below:

How to Winterize an Irrigation System

Well, its that time of year again. The leaves are starting to fall and temperatures are starting to drop. This also means its time to shut down our irrigation system. Here in the northeast (the writer of this article is from Michigan) our irrigation systems have to winterized to avoid damage caused by freezing temperatures. By taking the necessary steps for protecting our irrigation system now, will avoid costly repairs in the springtime.

First there are some claims of irrigation systems being self-draining. This might be true, however is it worth the gamble? Drains can get clogged or forgotten to be opened, water can be trapped in low spots; the list goes on and on. For the added safety and fairly low cost of winterizing with an air compressor, it’s not worth the gamble. Blowing out our irrigation system with an air compressor has been proven to be the best method being used today.

The following is the procedures for winterizing a typical scenario here in Michigan. Obviously, throughout the country the products and scenarios may be different, but generally the sequence of procedures are usually the same.

First and foremost, turn off the water! There will always be a master shut off valve somewhere. In the basement, crawl space or utility room would be the first place I would check.. Turn it off and tag it for future reference. Placing a tag on the valve indicating it’s for the irrigation system will prevent any mishaps that could happen for an unknowing homeowner.

Next manually drain the system (as much as we can). This will alleviate the pressure off the system and give us a head start on the winterizing process. Usually, opening a hose bib or drain on the backflow preventor will do nicely. Sometimes there is a drain inside the house. Obviously, we have to use a bucket to catch any drained water. Warning, you might get wet. Opening a drain under pressure will shoot water out for the first few seconds, until the pressure locked in the system dies down. Once the pressure has been bled from the system and the water has drained down a little, its time to hook up the compressor.

We will have to find an access to the system where we can hook up the air compressor. There has to be a hose bib or a drain somewhere after the main shutoff valve where we can attach the compressor hose. It will probably be the same drain we used in the previous sequence. Make sure all the other drains are closed (if we opened them in the previous step) except for the drain we are attaching our hose to. Sometimes we have to use a little ingenuity to make up a fitting to attach from the air hose to the drain. It’s usually never a standard fitting (unless your really lucky).

Prior to hooking up the air hose to the irrigation system, let the Air compressor charge itself. Usually, most compressors can charge up to 120 PSI or more. However, we do not need that much pressure to blow out our system. Actually, never blow out an irrigation system with more than 80 PSI Max. Be warned, anything over 80 PSI can damage the components of the irrigation system. Actually, I prefer to keep my air pressure around 60 PSI. Why? Because my house water pressure is 60 PSI, thus I should use the same amount of air pressure for winterizing. This will avoid any risks of using too much pressure.

Now hook up the compressor and start winterizing. Its best to start with the furthest away zone first and work our way back to the nearest zone. Or start on the zone at the highest elevation point. Usually on top of a berm or hill. Now, lets guess that zone number 10 is the furthest away zone. We turn zone number 10 on at the controller for 2 minutes and let it go. Now, 2 minutes might be too long or not long enough. Watch the water as it comes out of the sprinkler heads. Slowly the water will turn into a mist. Then the mist will turn into air. At this point all the air is out of zone number 10. Turn off zone number 10 and continue on to the next zone.

Please note, usually we do not have to get every single drop of water out of the system. If we continue to blow out the system (even though all the water is out), the heat from the air could damage the components of the irrigation system. Its better to get the majority of water out, but not continuously run the compressor trying to strive to get every drop of water out. A little residual water left in the zone will not hurt.

I recommend blowing out each zone twice with two short cycles as opposed to blowing out each zone once with a long cycle. This leaves less room for margin of error. I rather leave out a chance of having left the compressor on too long, or missing a zone, thus possibly damaging the system.

The compressor size needed depends on the system size. Usually bigger is better (and faster) but a smaller compressor can work, but it might take awhile. I usually recommend a compressor being able to deliver a MINIMUM of 60 PSI at 15 CFM’s. CFM’s is Cubic Feet per Minute. This is what actually displaces the water. Most compressors will not have a problem delivering the PSI, but it’s the CFM’s where they will lack.

Next, we have to check the backflow preventer. Most systems have a backflow prevention device installed at the beginning of the system. Make sure it’s completely void of water. Which it should be, because most likely we blew air through it to winterize the system. Open all the drains and leave them open. Over the winter, it’s best to leave the ball valves or drains (on the backflow preventor) at a 45-degree angle. Sometimes condensation can build up inside the ball valve, thus cracking it when the temperature drops below the freezing point. Leaving the ball valves at a 45-degree angle will help prevent this.

The average residential system should take about 30 to 45 minutes. But again, this all depends on the compressor size and the irrigation system size. Obviously, there are many more scenarios that can add to the winterization process. Pumps, fertilizer injectors, etc. all add to the winterization process. However this article covers the general sequence of the process.
Remember, “An once of prevention is worth a pound of cure”. This definitely applies to winterizing an irrigation system. Knowing that in the springtime our system will start and operate without any headaches is definitely worth a pound of cure.