David with C&K understood my noise problem from the beginning and spent time looking for it and testing the unit downstairs and checking the condenser until he was sure what was causing the vibration noise. He was thorough and polite and I would recommend him to anyone. He also was careful to keep his mask on at all times which is not an easy thing to do when he was going up and down the stairs. I also appreciate the text prior to the technicians arrival and David also phoned to let me know he would be at my house shortly.