Backflow preventers are often mounted above ground to meet local code requirements. The results is less protection from freezing tempertures. The backflow preventer should be drained and valves opened for the winter. In moderate winter enviroments the backflow cover can be insulated to protect the unit. In harsh climits the backflow can also be protected by heated tape.

Lateral lines and main lines carry the water to the spray heads and are generally buried 12 to 18 inches deep. The ground tempertures help protect these water lines from freezing. If you live in an area where the frost line is deeper than the main lines and lateral lines you can expect the lines to hard freeze so precautions must be taken. When winterizing water lines H2O-Matic evacuates water lines using compressed air.

  Control valves open and close selecting which zone will run. Typically they are buried underground but some installations place these valves above ground. Like the buried water lines the ground tempertures halp protect the valves. Because the valve boxes provide an air space the valves will freeze before the water lines. During winterization water is removed form the valves at the same time water is removed from the water lines. Above ground valves should be winterized in all but the mildest of climates.