I have been running my radiant floor heating for about 180 months. Works great other than one thing. I keep losing pressure in the closed loop system. I have four loops, with a single zone and pump. Running it off an on-demand water heater and normally set it at 20 psi.
Every couple of weeks I see that the pressure has dropped to around 3-5 psi. I hook up my drill to a small water pump and bring it back up to 20 psi. I cannot find any leaks, no water at all on the floor or spots where the pipe is leaking. This is getting old frankly and I simply don't have a clue at this point. I checked the expansion tank and it is at 12 psi.
The top of the loop of my system is about 6' off the ground.
If anyone has experience, thoughts or suggestions I would appreciate them.
Thanks in advance.