Loosen a seized sprinkler system control valve by applying a lubricant spray, like WD-40, and firmly gripping the valve with pliers to apply consistent pressure.

Now, release any remaining pressure in your sprinkler system using the valves on the backflow device, or via the manual drain valve. Be sure to close the valves again afterwards.

So if you attempt this method, make sure your air compressor can generate the 10 CFM (cubic feet per minute) required to execute this task and that your sprinkler system can handle the air ...

A sprinkler system employing automatic sprinklers attached to a piping system containing air or nitrogen under pressure, the release of which (from the open sprinklers) permits the water pressure to ...

Water pressure isn't just important for sinks and showers; it also matters to your sprinkler system. If your water pressure is too low, ... which could indicate that you have a damaged valve.