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Error code reference
Lennox Furnace Error Code LED Flashing 1/2 sec on 1/2 sec off
Lockout or Restricted Lockout condition on R7184B burner control (-5 units only).
SourceLennox O23/OHR23/OF23 Oil Furnace - Service Manualp. 13
Diagnostic procedure
The full LED Flashing 1/2 sec on 1/2 sec off procedure
Step 1 is visible so you can confirm you are on the right page. The remaining steps, the ones that tell you whether to actually replace a part, unlock with any pass.
MyPros+ · DiagnosticsStep 1 preview
1
First diagnostic step
Hold reset button for 30 seconds until LED flashes twice to clear restricted lockout.
SourceLennox O23/OHR23/OF23 Oil Furnace - Service Manualp. 13
More steps, wiring diagram references, and verified part numbers
Includes expected resistance and voltage values, connector pinouts, and supersession notes for replacement parts.
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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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