View Full Version : furnace ignites then after 10-25min cuts off
01-30-2013, 10:41 AM
Rookie tech working on a Sears brand furnace model 867.764221
The furnace comes on and stays lit for 10-25 min then shuts off. has a spark ignition that is also combination with the flame sensor. Is it a dirty flame sensor with a combination of a failed spark box? Used my multi meter and also turned on furnace disconnected
the flame/ignition sensor write and
01-30-2013, 10:44 AM
are you sure it is not tripping high limit? or even satisfing t=stat?
01-30-2013, 05:39 PM
Sounds like high limit like snupytcb said. Check airflow. Dirty blower wheel. Dirty filter or stopped up evap
01-30-2013, 07:31 PM
you should check air flow,make sure its not shutting off on high limit.Also make sure that prving switch is not loosing its draft ,may have clogged tube on the inducer.
01-30-2013, 11:36 PM
Is this a condensing furnace? The drain could be clogged and backing up.
01-31-2013, 12:11 PM
Check unit for proper gas pressure, furnace will tell you the minimum gas pressure required for the furnace. But like the other guys said, check air flow, flame sensor & check to see if you have proper draft.
01-31-2013, 12:20 PM
If it's running 10-25 minutes, I highly doubt it is a flame sensor or control board issue. As others have stated, cycling on limit, satisfying call for heat at the stat or plugged/restricted condensate drain.
Powered by vBulletin® Version 4.2.0 Copyright © 2013 vBulletin Solutions, Inc. All rights reserved.