What It Means
- Normal operation - signaled when heating demand initiated at thermostat.
Lennox Ducted Heating
Lennox Error Code SIMULTANEOUS FAST FLASH
Ducted Heating:
Causes & actions from Lennox
How it shows
- SureLight board LEDs (DS1/DS2): SIMULTANEOUS FAST FLASH (led1: flashing (fast), led2: flashing (fast))
- SureLight board LEDs (DS1/DS2): SIMULTANEOUS FAST FLASH (led1: flashing (fast), led2: flashing (fast))
- SureLight board LEDs (DS1/DS2): SIMULTANEOUS FAST FLASH (led1: flashing (fast), led2: flashing (fast))
This manual entry does not list further causes or actions.
Applicable models & manual sources
- G43UF
Normal operation − signaled when heating demand initiated at thermostat.
- G43UF
Normal operation − signaled when heating demand initiated at thermostat.
- G43UF
Normal operation − signaled when heating demand initiated at thermostat.
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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