10 — Furnace
One-hour soft lockout following repeated ignition or safety faults.
11 — Furnace
No flame proved during the trial-for-ignition period.
12 — Furnace
Flame established but microamp flame sense signal is weak.
13 — Furnace
Flame signal lost after successful ignition.
14 — Furnace
False flame signal detected while gas valve is de-energized.
22 — Furnace
Main limit switch open due to furnace high-temperature limit trip.
30 — Furnace
Low-voltage fuse open on control board.
33 — Furnace
Rollout limit switch open indicating dangerous flame rollout.
44 — Furnace
Low pressure switch closed while inducer motor is off.
45 — Furnace
Low pressure switch open while inducer runs at high speed.
46 — Furnace
Low pressure switch open while inducer runs at low speed.
55 — Furnace
High pressure switch closed while inducer motor is off.
57 — Furnace
High pressure switch open while inducer runs at high speed.
58 — Furnace
Water circuit or P4 jumper continuity open.
59 — Furnace
High secondary control voltage detected above normal range.
60 — Furnace
Non-critical blower airflow restriction fault.
61 — Furnace
Critical blower fault; blower motor unable to operate.
66 — Furnace
Blower operating at maximum speed/torque limit below target CFM.
68 — Furnace
Loss of communication between control board and ECM blower motor.
93 — Furnace
Internal control board processor malfunction detected.
d1 — Furnace
Missing or unreadable shared model data.
d3 — Furnace
Airflow CFM configuration mismatch between control and blower.
d4 — Furnace
Invalid or unreadable model data on installed memory card.
d6 — Furnace
Horsepower conflict between blower motor and memory card data.
d8 — Furnace
Obsolete or stale shared data detected on communicating control.
