Sprinkler System Winterizing

Shown below are the best methods to service your lawn sprinklers. Every year, before the first freeze, the ritual of sprinkler system "blow out" becomes the priority for all irrigation systems that are in regions of the country where the frost level extends below the depth of the installed piping. If you wait to long to schedule and complete this service costly damage can occur and resulting in necessary repairs the following spring. This service usually starts around September 1st and preferably no latter than the areas first freeze. 

Compressed Air Method

After safely connecting the compressor unit to the lawn sprinkler system. Each zone of the lawn sprinkler system needs to be activated starting from the furthest station / zone from the compressor slowly working your way to the closest station / zone to the compressor. Each station / zone should be activated until no water can be seen exiting the heads. On average each irrigation zone can take anywhere from 1 to 2 minutes. It is better to use two or three short cycles per station / zone than to have one long cycle for each zone. Once the station / zone is dry we do not continue to blow air through the pipe. Compressed air moving through dry irrigation lines / pipes can cause friction, which will create heat and the heat could cause damage by weakening the irrigation system parts.

Additional Steps

Once any remaining water has been removed from the lawn sprinkler system, release the air pressure slowly and then completely disconnect the air compressor and release any air pressure that may be present in the sprinkler system back flow device. If your back flow device or pressure vacuum breaker (PVB) has ball valves, open and close the isolation valves on the back flow device multiple times to make sure any trapped water has drained from the upper body. Leave the ball valves open / closed at a 45° angle (approximately 1/2 open) and open the test ports.

Manual Drain Method

Even the best lawn sprinklers need winter service. When manual sprinkler system irrigation valves are located at the end and low points of the irrigation piping. To drain these systems, simply shut off the irrigation water supply (shut off will be located in the basement and will be either a gate / globe valve, ball valve or stop and waste valve) and open all the manual drain valves slowly. Once the water has drained out of the irrigation system mainline, open the boiler drain valve or the drain cap on the stop and waste valve. And drain all the remaining water that is between the irrigation water shut off valve and the back flow device. Open the test cocks on the back flow device. If your lawn and garden sprinklers have check valves you'll need to pull up on the sprinklers to allow the water to drain out the bottom of the sprinkler body. Depending on the location of the drain valves, there could be some water left in the back flow, the piping and the sprinklers. When all the water has drained out, close all the manual drain valves.

Automatic Drain Method

Use when automatic drain valves are located at the end and low points of the lawn sprinkler or irrigation system piping. These will automatically open and drain water if the pressure in the piping is less than 10 PSI. To activate these, you shut off the irrigation water supply (shut off will be located in the basement in residential buildings and should be either a gate / globe valve, ball valve or stop and waste valve and activate a zone on the sprinkler system station to relieve the water system pressure. Once the water has drained out of the mainline, open the boiler drain valve or the drain cap on the stop and waste valve. And drain the remaining water that is between the irrigation water shut off valve and the back flow device. Open the test cocks on the back flow device. If your sprinklers have check valves you'll need to pull up on the sprinklers to allow the water to drain out the bottom of the sprinkler body. Depending on the location of the drain valves, there could be some water left in the back flow, the piping and in the sprinklers.

In some areas you might have a combination of the manual drain system on the mainline (the pipe between the irrigation water shut off valve and the valves) and auto drain system on the lateral lines (the pipe between the valves and the sprinklers).

We offer lawn sprinkler system design, sprinkler installation, drip irrigation systems, rain and money saving retrofits to existing lawn irrigation systems. We service Andover, North Andover, Lawrence, Methuen, and adjacent towns in the Merrimack Valley and southern New Hampshire. You will not find a better company to work with than Low Cost Sprinklers. You really need and really should call us today (978) 687-2152