______________________________________________________________________ I had hardwood floors put in recently, that apparently threw up enough dust to reduce the airflow of my 80UGH and stop it from working. Service tech came and said that after three restarts, the system had tripped some sort of safety. We cleaned the filters, and he got the system up and working again. A week later, my second zone heater just did the same thing. I’ve cleaned the filters, but don’t know how to reset the unit. Any guidance folks can provide to save me from a second service call? Cold and shivering in Zone 2 Replies: moondog “Re(1):Service Help w/ Lennox 80UHG Gas Furnac” , posted Sat 3 Dec 16:01 ______________________________________________________________________ Take off the door cover and find the schematic. Find the wires going to a small button switch near the burners and above them. The one above is probably the high limit switch which resets automatically unless it is stuck (due to too many resets or excessive temperature caused by floor sanders or lazy homeowners). The roll out safety switch has a small button between the two wires which when pushed, resets the switch. If one of theses types needs to be reset, find out why it is tripping, don’t just keep resetting it. To all that sand floors or walls—heat the house first, turn off furnace and then work….change filters often during construction……they never do though. PhilipH “Service Help w/ Lennox 80UHG Gas Furnace” , posted Sat 3 Dec 17:32 ______________________________________________________________________ Thanks so much! That did the trick! My puppies and I are very grateful! acefurnacefixer “Re(1):Service Help w/ Lennox 80UHG Gas Furnac” , posted Sat 3 Dec 12:58 ______________________________________________________________________ The high limits are not resetable so to speak, some flame roll outs are. Now if you remove the open high limit and smack it on a hard surface, sometimes it will snap back to the closed postion. Yes! I CAN fix that! PhilipH “Re(2):Service Help w/ Lennox 80UHG Gas Furnac” , posted Sat 3 Dec 13:03 ______________________________________________________________________ How do I identify the “open high limit” to do this?