1998 trane gas furnace. Upon arrival customer mentioned she turned unit up to 69 from 65 and unit did not kick on. When I set the thermostat it was set at 63 with a room temperature of 66. After I set thermostat to call for heat sensor unit fired up and ran normal operation. Ran performance testing on unit. Temp rise is 45 degrees. Combustion analysis showed 2 ppm CO/ 8% O2/ 330 degrees stack temp. Filter is in good shape and is a 201. Tested thermostat within one degree and found no issues with thermostat. Thermostat slightly confusing to read and could have been read backwards. Discussed thermostat operation with customer. Checked components in unit and found voltage absorption system for air movement motor out of specs. Recommended replacement to prevent premature failure of motor. Showed options on page hn4. Customer chose hn4c. Replaced voltage absorption system and upgraded. Replaced ignition system and upgraded. Cycled unit several times. All okay at this time.
