Upon arrival spoke with customer. He explained everything going on so we went to thermostat. Stat was set to heat and was set up but system was not running. We went downstairs and he showed me where the filter was very dirty and he changed it. Coil is clear, wires all tight. Started checking over system and was getting code for high limit switch. Started checking limits, one’s for flame roll out and they are working correctly. Found high limit sensor was tripped out. Pulled it out and tested again and it is cold to touch and tripped. Showed customer the sensor is bad. Explained I would try and call and see if the manufacturer is still open so we can get price/availability and if the system is under warranty. Was unable to get ahold of manufacturer so I explained to customer we would call first thing in the morning. Explained the membership and the reasonings behind having a loving air membership for his home. Customer did not want the membership I explained we would call him first thi