Control circuitry lockout. The control auto-resets after a 1-hour lockout caused by a flame-sense circuit failure, a gas-valve relay stuck open, or a software check error. Reset power to clear the lockout. Replace the control if the code repeats.
Bryant 45 is a control-circuitry lockout with a 1-hour auto-reset. The chart names a flame-sense circuit failure, a gas-valve relay stuck open, or a software check error. Reset power to clear it. Replace the control if 45 repeats. It is not ignition lockout 14, which is a 3-hour reset after four failed proving attempts.
Likely causes
- Flame-sense circuit failure
- Gas valve relay stuck open
- Software check error
Safe checks for 45
- Count 4 short flashes and 5 long flashes. The 1-hour reset is not a repair
- Technicianreset power once to clear the lockout. If 45 returns, replace the furnace control
Capacitors can hold a charge after the power is off. Safety terms.
When to call a pro
Call a licensed HVAC technician if 45 returns after one power reset. Do not keep resetting it overnight.
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Parts & tools for this fix
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Furnace control board and low-voltage fuse: guide
In this code: Parts list for this code: Furnace control board
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