Spring, Klein, and Champions lose more systems to a single freeze night than to a whole summer of heat. The backflow — usually a Febco 825 or Watts 009 — splits at the body. Water dumps at the meter. Heads look “broken” because nothing is reaching them.
On Spring sprinkler repair we isolate and rebuild or replace the backflow first, pressure-test, then walk heads. Insulate the device before the next front. If a zone is still dead after the backflow holds, then we open valve boxes.