I'm a semi-retired HVAC service tech with some install experience. I installed the AC system in my own home with the air handler in the attic. I forgot to put in a liquid line filter drier. Dumb mistake! Anyway, the lineset runs over my bedroom. When the AC runs at night when I'm in bed, I can hear a rattling sound. I've gone into the attic during the day and notice a gurgling, pulsing sound coming from where the lines enter the air handler. The system operates fine. I get pressures 205/62 at 80 degrees ambient with a 23 degree superheat and 13 degree subcool and an 18 degree temperature drop across the Ecoil. Real respectable, I'd say, but I can't help but wonder if something is amiss.