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Error code reference
Lennox Air Conditioner Error Code E411
The low pressure switch has opened 5 times within one hour, locking out the outdoor unit.
SourceLennox Air Conditioner - Service Manual: Elite Series XC20p. 31
Diagnostic procedure
The full E411 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
Confirm system is properly charged with refrigerant. Check for clogged TXV, blockage to indoor unit blower motor, dirty filters or clogged refrigerant filter. Clear after a power reset.
SourceLennox Air Conditioner - Service Manual: Elite Series XC20p. 31
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
2 manuals in the MyPros+ library document this code for Lennox air conditioner.
Models covered by the manuals that document this code
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