Strange pumping sound continues

   The strange pumping sound continues. Friday we heard it twice one at 10:01 and again at 11:00. Today (Saturday) it sounded very loud at 9:00AM. This is the first time its been heard it in the morning. My wife was in the diningroom and did not hear it. This evening it sounded at 8:01. The origin is a complete mystery. Hearing it in only one room makes no sense. Both the den and diningroom open directly into the library. The doorways are open, yet this sound, usually loud enough to be easily heard, is audible only in the library.