Lennox E403 Error Code
LSOM - Compressor short-cycling (Running less than 4 minutes). Outdoor unit pres
Source: slp99uhv-series__len-slp99uhv-english-iom.pdf
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Other Lennox Error Codes
Diagnostic Codes/Status of Equipment Soft lockout - Exceeded maximum number of A
. recycles. Last recycle failed due to the limit circuit opening or limit remain
E276 E290 E291 E292 Soft lockout - Flame sensed out of sequence from code 241 fa
Combustion air inducer motor amp draw is too Check combustion blower bearings, w
Indoor blower motor temperature is too high. Indoor blower motor over temperatur
Discharge error sensor failure - No error if Discharge air temperature(DATS) out
Heat rate reduced to match indoor blower air Furnace blower in cutback mode due
Restricted air flow in cooling or continuous fan Restricted airflow - Indoor blo
Indoor or outdoor unit capacity mismatch. Incorrect Indoor /outdoor capacity cod
E347 E348 E349 Global network connection - Communication link problem. No 24 Vol
communicating outdoor unit (Dual fuel module required for heat pump application)
LSOM - Outdoor unit system pressure trip. Compressor ran over 18 hours in air co