View Full Version : Armstrong ultra 80 furnace

Jan 5, 2018, 08:43 PM
Trouble shooting what caused will light flame will out in minutes

Jan 6, 2018, 09:55 AM
Couple of things to check. Make sure the filter is clean since reduced airflow can cause the hi temp limit switch to shut the heater down. Make sure the flue is clear/clean. An 80% heater will have a metal flue. Make sure the flue exhaust isn't covered in snow, leaves etc. Make sure you have adequate airflow into the front of the heater.