Im going to be relocating some pipe work in a kitchen in the next week or so. Part of that will require me to dig up the concrete floor and re route the pipe by soldering a joint to the existing pipe work that gets dug up. ( this will need to remain below floor level) My question is how can ensure the system is completely drained and dry? (Or at the very least in the area where I need to solder some joints to the existing the pipe work that I will dig up?) I’ve drained the system before but the lowest drain off point I can use is a few inches above floor level which means there’s always that extra bit of water in the pipes that are buried in the floor. Anyone got any tips to ensure the area is completely clear of any residual water before attempting to solder anything?