My furnace seems to not restart when it is below zero Celsius (in Canada) outside. It tries about 3 times and then stops (safety feature on furnace) I replaced the HSI and Flame sensor. Works wonderfully to temp. set on thermostat until it gets really cold outside. Have not checked the chimney yet to see if it is clogged.
I don't get error codes. There is no snow around vent/chimney. If I understand my manual the intake and outtake are one unit and come out of roof not wall.
When I wrote I don't get error codes I meant I don't have any display panel with codes or lights.