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.
The low pressure switch has opened 5 times within one hour, locking out the outdoor unit.
First step from the service manual
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.
The complete diagnostic procedure includes additional test steps, resistance specifications, wiring diagram references, and component test points.
MyPros+ Max
Get the full diagnostic procedure for E411.
- Step-by-step tests with expected resistance, voltage, and continuity values
- Wiring diagram references and connector pinouts from the OEM service manual
- Verified part numbers when replacement is required
Get the full procedure
$29/month · Cancel anytime · Or $9.95 3-day pass
78,000+ service manuals · 160,000+ error codes · 55+ brands
Get Started$29/month · Cancel anytime · Or $9.95 3-day pass