Fan control arrangement for a two stage furnace

摘要

The present invention involves a two stage furnace and a method of controlling the fans. In the furnace, a high pressure switch indicates whether sufficient air is present to support high combustion. Normally the furnace operates at one of the combustion settings. The circulator fan operates at the high speed setting when the high pressure switch indicates that sufficient air is present for high combustion, and operates at the low speed setting when the high pressure switch indicates that insufficient air is present for high combustion.