24.1
Low-voltage fuse needs replacement / fuse open
This code typically points to
- Short in 24 VAC wiring
- Thermostat, outdoor contactor coil, humidifier, accessory, or harness short
Next checks to confirm
- Isolate low-voltage branches
- Inspect thermostat/outdoor/accessory wiring
- Replace fuse only after short path is corrected
Escalation
Repeated 24.1 means real short, not nuisance fuse failure.
Reset behavior
Clears when fuse is replaced and the short is removed.
Urgent
Fix now