If it's a "manifold" style you should be able to isolate the bad circuit and reroute a new one.
Shut down Hot water to try and determine H or C.
Do you know if they put the pex in conduits or just poured into place?
The hoses are run in pvc conduits.
Problem is, the manifold doesn't seem to still work 100%. Some of the circuits, when the lever is thrown, it doesn't seem to completely shut the water off.
