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Error code reference
Lennox Furnace Error Code Heartbeat
Normal operation - signaled when heating demand initiated at thermostat (Board 100869). Constant 1/2 second bright and 1/2 second dim cycles.
SourceLennox G61MP Series - Service Manual: Gas Furnacep. 15
Where this code is documented
1 manual in the MyPros+ library documents this code for Lennox furnace.
Models covered by the manuals that document this code
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