Oh my gosh! Our heat pump heater was not working all day and it was working fine yesterday. The thermostat went blank today so we replaced the batteries, nothing. I replaced and filter and cleaned the grate surrounding, nothing. We rest the inside breaker, nothing. I was beginning to think I was going to have to call my Mom, our landlord (who is moving and stressed) and tell her that the unit wasn’t working. We literally just got it serviced and spent a pretty penny, about a month ago. I kept googling and reading, since the previous things mentioned didn’t work, and saw an article that said to reset the outside sub panel. (Keep in mind I literally have no idea about anything maintenance and had to google “what is a sub panel” 😂 ) Article said to reset the sub panel by turning it off for 2-3 mins and turn it back on and see if it fixed the problem. SURE AS SHIT I fixed it!!!!! Heater is back on and running!!! I just went and woke my husband up just to tell him that I FIXED IT!! YAY! I am so proud of myself and my Dad who passed away 9/2021 would be so proud of me too! Who would have thought that I could use google and fix our central heat unit, not me!!