im a plumber by trade,grabed by the nuts and thrown into a hvac system ive never heard of(lg sync 2) been told the basics of the system, and no problem with the piping, first test of the piping will not maintain pressure. all braze joints,schrader valves,flare joint,test rigs have been soap tested more time than i care to discuss.is there an issue with pressure fluctuation that i wasnt told about? any info will be greatly appreciated.