Fixing a broken sprinkler line can be tricky. Accessing the broken section and patching in a new piece is awkward, at best. Getting couplings and a new segment of pipe to fit requires bending and flexing pipes, which can be nearly impossible when the sprinkler lines are buried.
A simplified method of repairing a broken sprinkler line is to use a telescopic repair coupling. During installation, the coupling can be shortened slightly to position the piece between the severed ends of the sprinkler line, then lengthened into place to secure the joints. It is an excellent method when you have limited space to make the repair.
Source: The Spruce