Lennox Error Code LED#1-On, LED#2-Slow Flash

Possible cause: 1.2.1 Roll−out switch open. Corresponding action/comments: ACTION 1 − Manually reset the roll−out switch by pushing the top button. ACTION 2 − Determine the cause of the roll−out switch activation before leaving furnace. Possible cause: 1.2.2 Roll−out switch failure. Corresponding action/comments: ACTION 1 − Check continuity across roll−out switch. Replace roll−out switch if switch is reset but does not have continuity. Possible cause: 1.2.3 MMiisswiirriinngg oorr improper connections aatt roll−out switch. Corresponding action/comments: ACTION 11 −− Check wiring connections ttoo switch. Possible cause: 1.2.4 Nine pin connector failure Corresponding action/comments: ACTION 1 − Check 9−pin connector for proper connection to control board. ACTION 2 − Check continuity of the multi plug pin.

Possible cause: 6.3.1 Unit is firing above 100% of the nameplate input. Corresponding action/comments: ACTION 1 − Check that the manifold pressure matches value listed on nameplate. See installa- tion instructions for proper procedure. ACTION 2 − Verify that the installed orifice size match the size listed on the nameplate or instal- lation instructions. ACTION 3 − Check gas valve sensing hose to in- sure no leaks are present. ACTION 4 − Check the input rate to verify rate matches value listed on nameplate. Possible cause: 6.3.2 Gas orifices leak at the manifold con- nection. Corresponding action/comments: ACTION 1 − Tighten orifice until leak is sealed. NOTE: Be careful not to strip orifice threads. AC- TION 2 − Check for gas leakage at the threaded orifice connection. Use approved method for leak detection (see unit instructions). Possible cause: 6.3.3 Insufficient flow through the heat ex- changer caused by a sooted or re- stricted heat exchanger. Corresponding action/comments: ACTION 1 − Check for sooting deposits or other restrictions in the heat exchanger assembly. Clean assembly as outlined in instruction manu- al. ACTION 2 − For G24M gas furnaces, check for proper combustion and flow. CO2 should mea- sure between 6.0% and 8.0% for NG and be- tween 6.5% and 8.5% for LP. CO should mea- sure below .04% (400PPM) in an air−free sample of flue gases for either NG or LP. Possible cause: 6.3.4 Burners are not properly located in the burner box. Corresponding action/comments: ACTION 1 − Check that the burners are firing into the center of the heat exchanger openings. Cor- rect the location of the burners if necessary.