Furnace blower fan speed
I recently replaced the blower motor on my Ducane 125,000 BTUh furnace. It called for a 3/4 HP, 1075 RPM 11.7 amp. I am not getting the desired RPM's out of the motor as my airflow is poor. The fan can barely push the cooled air up to the second floor. The black high speed fan lead is on the "cool" terminal on the Honeywell control board model ST9120C-2010. I had the motor shop test the fan ahead of time in the squirrel cage fan and housing and it was spinning at the desired rpm and amperage draw. I am convinced the controller is the culprit. Is there a way to program the controller to speed up the fan? There is a "speed up" terminal on the board just above the thermostat terminals.
Thank you for any help you can give!
Last edited by Bfam4; 07-22-2012 at 07:50 AM.