FieldBench
Lennox codes

Lennox

E115

Lockout

Low 24V

Secondary below ~18–30 V class. Control restarts if voltage recovers.

Walk E115 in Diagnose

2 plates — walk the one on the cabinet

First check

1 Measure at the IFC under load

On Lennox EL195NE line-voltage codes are incoming power. Measure L1/L2 (or L1/N) at the board while it is trying to run, not just at the disconnect. 24 VAC at the IFC under load. Extra accessories robbing the transformer.

Expect: Voltage in the rating-plate window under load.

The rest of the walkthrough is Diagnose.

On the plates

  • 24 VAC at the IFC under load. Extra accessories robbing the transformer.
  • Door-switch / shorted valve / undersized VA. Fix the load before you upsize the transformer.

Plates that use E115