I installed a pex water line to an outbuilding several years ago, about 150' long, buried in 18" trench. The line was disconnected for over 3 years and I recently reconnected it and no water is reaching the outbuilding. I have removed all fittings on the far end and have open pipe, and I can hear the line pressurize when I open a valve on the supply side but there is no indication of flow.
I added a tee for testing and the buried line holds pressure when isolated for hours, so it is not leaking underground. There are no turns or bends where a kink could form. The only cause I can think of is that the line collapsed. The line is buried with an electric conduit and it would be a major effort to hand dig the line again.
Will leaving the line pressurized reverse the collapse? Is there anything I can do to aid the process?
UPDATE to questions in comments: The line is 1/2" PEX B, typical residential line. There has been a little traffic over the area where the line is buried, with a small tractor and pickup truck driven over the area perhaps 20 times. When disconnected, one end of the line had a hose bibb installed and the other was covered with tape, not airtight.