Closed loop system using glycol antifreeze, has 6 zone valves. Set pressure to 15# and within a week it drops to 10#. Set to 15# again and drops to 10# again.No visible leaks, but some pipes in wall and under a slab of cement. Is their a sealer I can put in the system?
howtomendit.com for free repair help, information and advice.
Try fixfault.com to fix home heating systems.