Every year at the beginning of the warm season, you should perform a "Spring Tune Up" on your lawn irrigation system. During the late fall and winter seasons many systems lay dormant and now need to be fired back up for regular use. However, care should be taken before you just start blasting away, or you could be blasting a hole in your wallet.
Initial System Prep:
Well & Pump Systems: If your irrigation system is tied to a well & pump, you will have to prime your pump back up if you drained it. Although many people prefer to fully drain their pumps, it is not required as long as you provide sufficient insulation for your pump to keep it from freezing. Of course if it gets colder than normal, you may find that you should have insulated it more than you thought.
There is simply nothing like dry, water free equipment when it comes to subfreezing temperatures. Even if you did not drain your pump, it may still need to be re-primed because of a check valve or vacuum leak. To prime your pump, simply pour water into the pump housing. (volute) Most pumps usually take about one or two gallons to prime, but can vary. Your pump should have some sort of valve or cover where you are able to put prime water in the pump.
If not, you will need to install one by cutting the PVC at the discharge (outlet) and insert a valve or faucet so you can fill the housing with water. (Might want to install it with the hose connector cocked slightly to one side for easier access.) Remember, even self-priming pumps sometimes need to be primed, especially if they are older. These are usually the ones where you will need to add your own priming valve.
Municipal or Pressurized Water Systems: In some areas, municipal code requires an anti-suction or vacuum-breaker valve to be installed on the irrigation system. In my area, it also requires the valve to be 18 inches above ground. Some people use various methods to cover the valve both for Winter protection and aesthetics. They use a cover or fake rock or something, but when spring comes, they find themselves shelling out 250-300 dollars to replace it. I just cut mine off. Yep, I installed quick connect couplers like what the plumber uses on kitchen sink drains, and I just screw them off for Winter and back on for Spring. I store the valve on a little shelf in my garage until it's time to go back to work.
System Pressurization and Inspection
Static Leakage Inspection: Once you are ready turn your system on, it's time to go through initial inspection and start up phase. You will need to pressurize your system by starting your pump(s), if you have them, or turning on the master valve to the municipal water supply, but not the timer. We don't want to actually start squirting any water yet. At this point, go around looking at all exposed fittings for leakage. Remove any and all solenoid cover plates and anywhere you have access to any parts of the system. Keep in mind that late growth may have covered some access panels. If you find any leakage, mark down what and where you found it. If it's too bad to go on, then you will have to stop here and do maintenance before continuing.
Read Full Article Here: Getting Your Lawn Sprinklers Ready For Spring
