Lennox Ducted Heating

Lennox Error Code LED #1 OFF / LED #2 Slow Flash

Ducted Heating:

What It Means

  • During operation pressure CLOSED? NO: gas valve de-energized, combustion inducer ON, indoor blower OFF with delay. LED1 OFF AND LED2 SLOW flash. Switch CLOSED within2.5minutes? NO:5minute pressure Watchguard then retry. Inducer ON here must not merge with page27 OFF behavior.

Causes & actions from Lennox

How it shows
  • SureLight board LEDs (DS1/DS2): LED #1 OFF / LED #2 Slow Flash (led1: off, led2: flashing (slow))

Combustion air pressure switch open. Gas valve de-energized, combustion air inducer on, indoor blower off with delay. If switch fails to close within 2.5 minutes, enters 5-minute pressure switch Watchguard mode.

Applicable models & manual sources
  • G24M

    During operation pressure CLOSED? NO: gas valve de-energized, combustion inducer ON, indoor blower OFF with delay. LED1 OFF AND LED2 SLOW flash. Switch CLOSED within2.5minutes? NO:5minute pressure Watchguard then retry. Inducer ON here must not merge with page27 OFF behavior.

    G24M manual, page 28

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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