Furnace throwing high limit lockout fault (13) Adjusted temperature rise to maintain a steady 52⁰ Furnace would run 10 min or so and go into a 13 fault, never showed a 33 fault (33 fault MUST occurr before the 13 fault shows up) Sometimes it would be right back to a 13 fault after resetting the power While this was happening, using a volt meter, the high limit circuit was being monitored. Not once did the limit circuit actually open up when the 13 fault would occurr. Replaced control board Due to age and alleged history of refrigerant top off every summer for the past 5 years, recommend replacement of the system.
