Installed a 3 ton 410a American Standard heat pump condenser with a new lineset. I put 100psi pressure test on lineset and detected no leak . then pulled vaccum and still no leak. when i cracked the valves open and and released refrigerant. A weld gave way on the 3/8 line just enough to make a small drip of oil appear. Step by step what should i do ?? Any advice would be greatly appreciated thank you.