Not a guarantee or warranty. These steps could prevent damage to your sprinkler system. In order to blow the water out of your sprinkler system it must be working. You might have ice in your system. I need you to do the following steps ASAP. 1. Turn on the water to your sprinkler system. 2. Turn on your sprinkler system timer/controller and activate the manual setting. The manual setting will activate your sprinklers. 3. Check If water comes out of your sprinklers. If you have water coming out skip to step 6 4. Make sure your timer is on manual setting and your water on. 5. Pour buckets of hot water on your backflow preventer, all pipes leading to backflow preventer from the house and into the ground and/or across the ground leading to your sprinklers. Do this until water comes out of your sprinkler system. You can also use cold water from a hose (even cold water will melt ice, it just takes longer) 6. After you successfully get water coming out of your sprinkler system. Leave your timer on and shut off the water supply inside your home to the sprinkler system. If you have a drain plug remove it. If you have a faucet for a hose open it. On the backflow preventer there are 2 large valves with handles and 2 small valves. All four of these need to be opened to 45 degrees. The two small ones require a flathead screwdriver to turn. 7. With the water supply in the house turned off. Manually cycle through each zone of your sprinkler system using your sprinkler system timer for 30 seconds per zone.