Is It Necessary to Winterize an Unused Sprinkler System?

Pipes

• Water travels through underground PVC pipes in most sprinkler systems. These pipes are durable and resist corrosion well. However, they can crack easily when water freezes inside and expands. The expanding water has nowhere to go, so it bursts the side walls of the pipe. Blowing out these pipes is critical so that water does not remain in the pipes during especially cold weather.

Manifolds

• Sprinkler manifolds are the heart of your system. They consist of a main supply pipe with a series of valves attached. These valves control the flow of water to each zone on the sprinkler system. The manifold is also made out of PVC plastic, so it must be fully drained of water to protect the pipe and the valves above. If left full of water, the manifold can crack, leading to a potentially costly repair.

Sprinkler Heads

• Each sprinkler head sits in a self-contained body. These bodies are usually made out of a thin plastic that can crack when frozen water expands. Because the sprinkler heads are attached to the supply pipe, blowing out the pipe will also blow out the sprinkler bodies, protecting them from cold weather damage. Sprinkler heads also can be removed completely by digging out the area around them and turning the body counterclockwise until the heads pull free from the ground.

Pressure Vacuum Breaker

• The vacuum breaker is an important part of any sprinkler system. These devices, which are installed above the manifold, keep water from flowing back into the main line. In most cities, a vacuum breaker is required by code as a safety device. Water can sit inside these devices, which are made out of brass. As frozen water expands, it can damage the internal springs or crack the brass housing. The vacuum breaker is usually the most expensive part of a sprinkler system, so you should blow out these devices when winterizing.