How to Winterize an Irrigation System
It’s 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 and winterize to avoid damage caused by freezing temperatures. 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 left un-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 your irrigation system with an air compressor has been proven to be the best method being used today.
This article outlines the procedures for winterizing a typical system. Obviously, throughout the country the products and scenarios may be different, but generally the sequence of procedures is usually the same.
There are two possibilities of water source for your home. If you have a backflow installed, you are using city water (very few Moss Creek residents have this option) or you run your system on the Community well water.
First and foremost, wait until the Community Irrigation Specialist has turned off the Community system for the season. We plan to shut the system down on Saturday October 31st, weather permitting assuming we do not have a late streak of high temperatures.
For residents on backflow only, you will manually drain the system (as much as you can). This will alleviate the pressure off the system and give us a head start on the winterizing process. 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. If you use the Community system, draining the lines of your system is not an option.
Next, you will have to hook up the air compressor at the source of your water, be it the backflow or the ball valve for those using regular Community Irrigation. There has to be a point of connection. If there is not one there, one must be installed. If you have ever winterized your system, you will have this point of connection. 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 you’re 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, it is best to keep the air pressure around 60 PSI. 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 zone first and work your way back to the nearest zone. Or start on the zone at the highest elevation point, usually on top of a berm or hill. Say zone number 4 is the furthest away zone. You will turn zone number 4 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 4. Turn off zone number 4 and continue on to the next zone.
Please note, usually you do not have to get every single drop of water out of the system. If you 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. It’s better to get the majority of water out, but not continuously run the compressor trying to strive to get every drop of water. A little residual water left in the zone will not hurt. It is recommended to blow out each zone twice with two short cycles as opposed to blowing out each zone once with a long cycle. This leaves less of a margin for error and eliminates the chance of leaving the compressor on too long.
The compressor size needed depends on the system size. Usually bigger is better (and faster) but a smaller compressor can work though it might take a little longer. The recommended size compressor should be able to deliver a MINIMUM of 60 PSI at 15 CFM's (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 they may lack.
If you have a backflow system, check the backflow preventor. These systems have a backflow prevention device installed at the beginning of the system to keep dirty water from flowing back into the clean city water pipeline. Make sure it's completely void of water. Open all the drains and leave them open. Over the winter, it's best to leave the ball valves (what most moss Creek residents have) 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. However, this article covers the general process. Remember, "An ounce of prevention is worth a pound of cure". This definitely applies to winterizing an irrigation system. Knowing that in the springtime your system will start and operate without any headaches is definitely worth the effort of preventative measures.
By Damian Zawacki of John Deere; edited by Kuester Management staff