Bradford White Water Heater Error Code 23

Error code 23 means the control board detected a flame signal before the ignition sequence was initiated. This is a safety lockout condition indicating the system sensed combustion at a time when the burner should not be active. The water heater will shut down and refuse to operate until the cause is diagnosed and resolved.

Yes, this error code should be taken seriously. A flame detected before ignition can indicate a gas valve that is not closing properly or other combustion control issues. Do not attempt to bypass the lockout. If you suspect a gas leak or smell gas near the unit, shut off the gas supply and contact a qualified technician or your gas utility immediately.

Repair costs depend on the faulty component. A flame sensor replacement is typically the least expensive fix, with parts and labor ranging from around $75 to $200. A gas valve replacement is more involved and can range from $200 to $500 or more depending on labor rates and the specific model. Control board replacement falls in a similar range. A diagnostic service call alone may cost $75 to $150 before any parts are factored in.

You may be able to clear the lockout temporarily by resetting the unit, but if the underlying cause is not corrected, error code 23 will return. A reset does not fix a faulty flame sensor, a leaking gas valve, or a wiring short. Resetting repeatedly without diagnosing the root cause is not recommended and could mask a potentially unsafe condition.

Start by inspecting the flame sensor rod for contamination, damage, or a shorted wire in the sensor lead. If the sensor appears clean and the wiring is intact, the gas valve should be evaluated to confirm it closes fully between cycles. If both components check out, the control board may need to be tested or replaced. Given the safety implications of this error, many homeowners choose to have a licensed plumber or HVAC technician perform this diagnosis.