Concern: Should the circuit board is terrible, would the furnace function in any way? My furnace operates fantastic from time to time, but a few occasions every day, ordinarily in the nighttime, it blows out cold air only. Two techs have informed me circuit board is fine, however the 3rd http://heating-and-furnace-repai72615.timeblog.net/36574879/air-conditioning-repair-fundamentals-explained