What It Means
- Heat rate reduced to match indoor blower air flow.
- SLP98UHV, SLP99UHV: Heat rate reduced to match indoor blower air flow. Replace filter or repair duct restriction.
Lennox Ducted Heating
Lennox Error Code E311
Ducted Heating
E311 means different things on different Ducted Heating models. Enter your model number to see only your reading, or find your model below.
Causes & actions from Lennox
Heat rate reduced to match indoor blower air flow.
11 models
ML296UHVK, ML297UH045XV36BK, ML297UH070XV36BK, ML297UH090XV36CK, ML297UH090XV60CK, ML297UH110XV60CK, ML297UH135XV60DK, ML297UHVK, SL280DFNV, SL280UHV, SL297UHNV
Gas furnace (indoor)
How it shows
- Integrated control 7-segment display: E311
Warning Only. Furnace blower in cutback mode due to restricted airflow. Reduce firing rate every 60 seconds to match available CFM. Check filter and duct system. To clear, replace filter if needed or repair/ add duct. 2-stage controls will reduce firing rate to 1st stage. Clears when heat call finishes successfully.
Other manual wording
ML296UHVK, ML297UH045XV36BK, ML297UH070XV36BK, ML297UH090XV36CK, ML297UH090XV60CK, ML297UH110XV60CK, ML297UH135XV60DK, ML297UHVK
Warning Only. Furnace blower in cutback mode due to restricted airflow. Reduce firing rate every 60 seconds to match available CFM. Check filter and duct sytem. To clear, replace filter if needed or repair/add duct. 2 stage controls will reduce firing rate to 1st stage. Clears when heat call finishes successfully
Applicable models & manual sources
- SL280DFNV
Heat rate reduced to match indoor blower air flow.
- SL280UHV
Heat rate reduced to match indoor blower air flow.
- SL297UHNV
Heat rate reduced to match indoor blower air flow.
- ML296UHVK
Heat rate reduced to match indoor blower air flow.
- ML297UH045XV36BK
Heat rate reduced to match indoor blower air flow.
ML297UH045XV36BK, ML297UH070XV36BK, ML297UH090XV36CK, ML297UH090XV60CK, ML297UH110XV60CK, ML297UH135XV60DK, ML297UHVK
Heat rate reduced to match indoor blower air flow. Replace filter or repair duct restriction.
Models: SLP98UHV, SLP99UHV
How it shows
- Integrated control 7-segment display: E311
Furnace blower in cutback mode due to restricted airflow. Check filter and ductwork. To clear replace filter if needed or repair/ add ductwork.
Applicable models & manual sources
- SLP98UHV
Heat rate reduced to match indoor blower air flow. Replace filter or repair duct restriction.
- SLP99UHV
Heat rate reduced to match indoor blower air flow. Replace filter or repair duct restriction.
Disclaimer: This information is for general reference. Code wording and instructions vary by model. Always follow the service manual for your exact unit.
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Continue in ACLogics with guided diagnosis for your equipment and symptoms.
