Fault Code Lookup

HVAC Sales Master

E151

Refrigerant leak detector sensor #1 fault

This code typically points to

Sensor failed or reporting internal fault

Next checks to confirm

Replace sensor if fault persists

Escalation

Sensor fault

Reset behavior

Clears when sensor no longer reports fault condition.

Safety Critical

Immediate concern

⚠ Cross-generation conflict

Codes E150, E151, E152, E154, E155, E160, E161, E163, E164, and E390 only exist on K-revision Lennox furnaces (EL195UHNEK, ML196UHEK). These are refrigerant leak detection codes for R-454B A2L compliance. E154/E155 will latch the blower ON for at least 5 minutes regardless of thermostat call — this is a code-mandated safety behavior. A2L refrigerant detection CANNOT be disabled — it's prohibited by safety codes.

Source

Lennox EL195UHNEK Installation Instructions 508575-01, p.46

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