FieldBench
Lennox codes

Lennox

Heat alarm

Lockout

Prodigy heat

Heat did not prove.

Walk Heat alarm in Diagnose

Sign in for the next measurement

First check

1 Write the live code and watch one cycle

On Lennox LGH read Prodigy unit controller (Landmark) before you pull power. Write Heat alarm exactly. Watch one full sequence and note which step dies. Prodigy heat alarm, then the ignition module LED in the heat section.

Expect: Call: Occupied / G starts the indoor fan. Y1 is cool. W is gas heat. They are different boards in the same box.

The rest of the walkthrough is Diagnose.

On the plates

  • Prodigy heat alarm, then the ignition module LED in the heat section.
  • Inducer, PS, HSI, valve, flame — same packaged-gas path.

Plates that use Heat alarm