Tips for winterizing a sprinkler include opening the boiler drain valve or draining the cap and waste valve and then draining the remaining water in between the irrigating shut-off valve and the backflow device. These procedures depend on the type of sprinkler used.
For a manual drain sprinkler, open the drain valve of the boiler once the water has drained, and drain all the water that is between the backflow device and the shut-off valve. The test cocks on the backflow should be opened. If the sprinkler has a check valve, pull it up to drain all water from the bottom. After draining all the water, close all the manual valves.
For an automatic sprinkler, drain all the water by opening the drain valve or cap and the waste valve. This enables draining of the water between the water shut-off valve and the backflow valve. The test cocks also need to be opened. Open the check valve if the sprinkler has one. Some water could remain between the piping and the backflow that needs to be drained.