When pressure-testing a Manabloc and PEX system with air, after rough-in, I shut off all valves on the Manabloc, leaving pressure in each individual line. When coming back to finish plumbing the house, I slowly cut lines or relieve faucet valves of pressure. If the line isn’t holding pressure, it needs further investigating as it could have been compromised by a screw or nail during sheet rock application or finish work. Small, slow leaks can be extremely damaging and costly for the customer.