45
Bryant
Control Circuit Lockout
Furnace LED shows code 45; furnace may lock out and require power cycling to restart.
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Safety Warning
This repair may involve working with high voltage components or water connections. Always unplug the appliance before removing any panels.
If you are not confident in your ability to perform this repair safely, we strongly recommend contacting a professional technician.
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Possible Causes
Multiple unresolved faults, control board software lockout, repeated limit or ignition failures
How to Fix / Troubleshooting
Safety first: Do not repeatedly reset a furnace that quickly returns to lockout without identifying the underlying cause.
- Record prior codes: Many Bryant boards flash a history code before 45. Note any previous codes to identify the root problem (e.g., 33 for limit, 14 for ignition).
- Power cycle: Turn off power for 60 seconds, then restore. Call for heat and observe the entire sequence to see which fault reappears.
- Address root cause: Use the earlier fault code (limit, pressure switch, ignition) to guide repairs rather than focusing only on 45.
Persistent lockout after addressing obvious issues (filter, venting, ignitor) requires professional diagnosis.
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Repair Difficulty
Hard
4/5
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