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Error code reference

Bradford White Water Heater Error Code 24

Flame detected after a heating cycle completes.

Bradford White codesBradford White water heater codes

Flame detected after a heating cycle completes.

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What 24 means on a Bradford White water heater

Error code 24 on a Bradford White water heater indicates that flame is being detected by the flame sensor after a heating cycle has ended and the gas valve has been commanded to close. Under normal operation, once the thermostat setpoint is reached and the burner shuts off, the flame sensor should detect no flame presence within a very short window. When the control board detects a flame signal persisting beyond that window, it logs code 24 as a safety lockout condition.

The most likely cause of this fault is a gas valve that is not fully closing when de-energized. If the valve seat is worn, debris-contaminated, or the solenoid coil is malfunctioning, a small amount of gas may continue to flow and sustain combustion after the control signal is removed. This is a serious condition because uncontrolled burner operation can lead to overheating and pressure buildup inside the tank.

A faulty or contaminated flame sensor can also contribute to this code. If the sensor rod has a carbonized coating or a grounded short, it may report a false flame signal to the control board even when no combustion is occurring. In either scenario, the unit should be treated as unsafe to operate until the root cause is confirmed and corrected. A qualified technician should verify both the gas valve operation and the flame sensor signal before returning the unit to service.

Source: manufacturer service documentation.

Common causes of 24

  1. 01

    Gas valve not closing fully

    Part replacement

    A worn valve seat, debris in the valve body, or a failing solenoid can prevent the gas valve from fully shutting off, allowing a small flame to persist after the cycle ends. This is the most serious cause and typically requires valve replacement.

  2. 02

    Contaminated or faulty flame sensor

    Wiring / connection

    Carbon buildup or corrosion on the flame sensor rod can cause it to send a false flame signal to the control board after the burner has shut down. Cleaning the sensor rod with fine steel wool may resolve this, but a damaged sensor will need replacement.

  3. 03

    Control board fault

    Part replacement

    If the control board is misinterpreting the flame sensor input due to an internal component failure, it may incorrectly log code 24 even when the gas valve and sensor are functioning correctly. This is diagnosed after ruling out the valve and sensor.

  4. 04

    Grounded or shorted flame sensor wiring

    Wiring / connection

    A pinched, melted, or chafed wire between the flame sensor and the control board can create a short that mimics a flame detection signal. Inspect the wiring harness for damage and confirm continuity and isolation from ground.

See the test procedure for each cause

Frequently asked questions about 24

What does 24 mean on a Bradford White water_heater?
Error code 24 means the heater is detecting a flame signal after the burner should have shut off at the end of a heating cycle. The control board monitors the flame sensor continuously, and if it sees a signal when the gas valve has been commanded closed, it triggers this lockout. This is a safety-critical fault that prevents the unit from operating until the issue is resolved.
Can I fix error code 24 myself?
Some causes, such as a dirty flame sensor, can be addressed by a knowledgeable DIYer with basic tools. However, if the gas valve is not closing properly, that repair involves the gas supply system and should only be performed by a licensed technician. Do not attempt to bypass or ignore this fault code, as persistent flame after shutoff is a genuine safety hazard.
Is error code 24 dangerous?
Yes, this code should be taken seriously. A burner that continues to fire after the thermostat is satisfied can cause the water temperature to rise beyond safe limits, potentially triggering the temperature and pressure relief valve or causing tank damage. Turn off the gas supply to the water heater and contact a technician promptly if you see this code.
Will resetting the water heater clear error code 24?
A reset may temporarily clear the lockout and allow the unit to attempt another heating cycle, but the code will return if the underlying cause is not corrected. If the gas valve is leaking or the flame sensor is faulty, resetting the unit without repair does not make it safe to operate. A reset is useful for confirming the fault is active, but it is not a fix.
How much does it cost to repair error code 24 on a Bradford White water heater?
Repair costs vary depending on the root cause. Cleaning a flame sensor is a relatively low-cost service call, typically in the range of $75 to $150 for labor. Replacing a gas valve is a more involved repair and parts plus labor can range from $200 to $500 or more depending on the model and local labor rates. Control board replacement falls in a similar range.

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