Before You Call For Service
1) Make sure your furnace air filter is clean. This filter is for air conditioning also. Click this text for important information on filters.
2) Check Light switch on or near furnace. This is the main power to the unit.
3) Check furnace breaker or fuse in main electrical panel. Air conditioning will have 2 fuses or a double wide breaker. Air conditioner also has a disconnect by the outdoor unit. This box may or may not have 2 fuses in it.
4) Make sure you have your furnace doors on right. There is a door switch that kills the power to the unit if not on right.
5) Hi-efficient furnaces (furnace that vents with plastic pipe) will have a drain system. Make sure it is not plugged. Carrier, Bryant, Payne drain trap is commonly plugged on 1994 - 2010 model. Click this text for video. Make sure vent pipes are not drifted over with snow or recirculating exaust back up into intake. This will frost over the intake and cause pressure switch fault code.