Restricted heat airflow: airflow is below the minimum, and the furnace is in a 1-hour soft lockout.
Homeowner part this code names: furnace air filter.
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Lennox E291 means heat airflow is below the minimum on an SL280DFNV, and the furnace is in a 1-hour soft lockout. The row names a dirty filter, other airflow restriction, and blower performance. It clears when a heat call finishes. E250 is the open limit circuit and does not use this filter sentence.
Likely causes
- Dirty filter
- Other airflow restriction
- Blower not meeting performance
Safe checks for E291
- Turn the furnace off and replace a dirty filter with the size printed on the old filter. Point the arrow the way the old one faced
- Make sure return and supply grilles are open
- Techniciancheck blower performance if a clean filter does not let the next heat call finish. The code clears when a heat call finishes successfully
Capacitors can hold a charge after the power is off. Safety terms.
When to call a pro
E291 is the airflow lockout, and the manual names a dirty filter. E250 is the open limit circuit and does not use that filter sentence. If a new filter does not clear E291, call a licensed HVAC technician.
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Parts & tools for this fix
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Furnace and AC air filter: guide
In this code: Dirty filter
Furnace blower (circulator) motor: guide
In this code: Blower not meeting performance
This one is for a technician to test or replace, so we only explain it and do not link to buy it.
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