Thanks all of you. I am scheduled for Wednesday for replacement of the "guts". I know, this is gambling in small way, as I could still land with drilling completely new well.
Need your opinion on my thoughts. When I shut the power going to the pump before leaving house for work, after coming back pressure drops almost to zero. I am sure that I do not have any leak and only device using water during my absence could be rather sizable RO system. But when I also shut main on water pipe, pressure stays at same level when I leave.
Would be this an indication that my pipe (that one 1" running inside 2" pipe) is solid without any breakage? From previous post you can read that I've tried to pull it out from the wall. However, I didn't use excessive force and stopped after short while.