manual works, auto doesn't - http://www.hvacmechanic.com/ Forums


Original message

TNFarmer

68.47.244.229

"manual works, auto doesn't" , posted Sun 19 Oct 12:41user profileedit/delete messagepost reply


The fan on my heater was not on this morning, but I could feel heat around the unit. I removed the cover and noted that the heater coils were working and the fan was not running. I noticed a switch for manual and tried it, the fan started. The thermostat was set at 70 and it was about 50 in the house so everything should have worked in auto. What do I need to fix?

 


Replies:

Houston204



98.196.66.53

"Re(1):manual works, auto doesn't" , posted Sun 19 Oct 13:23user profileedit/delete messagepost reply


Whatever normally brings in the fan with heat mode...

Electric heat: possibly a sequencer


Old gas furnace: check the fan limit


modern gas furnace: verify that the circuit board is sending power to the "heat" fan terminal

"Tip of the Day" Remember to remove power first.