Not Cold After Pipe Work: Where to Start on a Long Run

A room that cooled acceptably before pipe-route work and takes noticeably longer afterwards, with the outdoor unit running more of the hour to hold it. The run is long and partly hidden behind finishes, so most of what was touched cannot be seen from either end.

Only one of the two explanations is testable, and on a concealed run testing it costs more than it does anywhere else. Where pipework is exposed, every joint that was opened can be checked. Where it is buried, the candidates are unknown unless somebody wrote them down, and an unknown set is not a diagnosis.

Concealment does not change what fails. It changes who can prove it. Behind a finish the evidence is unreachable, so the reasoning stops being inspect-and-confirm and becomes narrow-and-infer. What narrows it is knowing which section was disturbed, and when. Absent that, a fault introduced by work is indistinguishable from ordinary decline, and ordinary decline is what gets quoted.

Correct the joint, prove it holds, then charge, which is the order on any run. The part specific to this one is what happens afterwards. Photographs and notes of what was opened, where, and when, kept by whoever owns the property rather than by whoever did the work. On a concealed route that record is the difference between a next diagnosis measured in hours and one measured in days.