After testing the diffuser from tips gathered online, I felt the diffuser was defective. I orderd the diffuser and thermistor (did not test thermistor) at about 4:30 PM on Fri afternoon. I paid up for quicker delivery, not next day, expecting to see the parts on Mon or Tues. Well the parts were at my home, at 3:30 Sat. from Kentucky to CT in 23 hrs, WOW!! I did a resistance check of new thermistor at room temp and later tested original when it warmed up, the original was fine, saved it in case ever needed. All appears to be working fine at this time