Bradford White Water Heater Pilot & Burner Assembly Replacement — What This Part Does
The pilot assembly on Bradford White gas water heaters generates a standing pilot flame that heats the thermopile to produce voltage for the gas control valve. The assembly includes the pilot burner, thermocouple or thermopile sensor, and igniter wire. When the thermopile produces over 400 millivolts, the gas control knows the pilot is lit and allows the main burner to fire on demand.
Pilot assemblies fail when the thermopile degrades and drops below 400 millivolts, the igniter wire breaks or shorts, or the pilot orifice clogs. Bradford White service procedures specify pilot assembly replacement when thermopile output falls under 400 mV, when spark is present at the gas control but not at the igniter lead, or when the pilot will not stay lit after following lighting instructions.
Signs It Needs Replacing
- Pilot lights but goes out immediately The flame ignites when you hold the button down but dies as soon as you release it, indicating the thermopile is not generating enough voltage to hold the gas control open.
- Thermopile reads under 400 millivolts Bradford White specifies that any reading under 400 mV after three minutes of pilot operation means the thermopile is bad and you need to replace the pilot assembly.
- No spark at the pilot tip You see spark at the gas control terminal when testing but no spark reaches the pilot burner, meaning the igniter wire in the pilot assembly has failed.
- Main burner will not fire even with pilot lit The pilot stays on but the main burner never energizes, often because thermopile voltage is too low to signal the gas control that it’s safe to open the main valve.
- Visible damage to igniter wire or pilot bracket The white igniter wire shows cracks, burns, or corrosion where it connects to the pilot, or the pilot bracket is bent and holding the flame away from the thermopile.
- Pilot flame is weak, yellow, or flickering A small or discolored flame that does not properly wrap around the thermopile tip will not generate the 400+ millivolts needed for gas control operation.
How to Replace It
- Turn off the gas supply at the manual shutoff valve on the gas line feeding the water heater.
- Set the gas control dial on the front of the heater to the OFF position and wait five minutes for any residual gas to clear.
- Locate the pilot supply tube and thermopile lead wires at the gas control valve and disconnect them by pulling the push-on connectors or loosening compression fittings per your model.
- Remove the burner access cover or door at the base of the water heater to expose the burner chamber.
- Slide out the main burner assembly (it usually lifts and pulls forward), then locate the pilot assembly bracket mounted near the burner or on the burner manifold.
- Unscrew or unclip the pilot assembly from its bracket, pull it free, and note the routing of the pilot tube and wires for reinstallation.
- Install the new pilot assembly in the same position, reconnect the pilot gas tube and thermopile leads to the gas control valve, and route the igniter wire along the original path.
- Reinstall the main burner assembly and access cover, turn on the gas supply, and follow the lighting instructions on the heater’s label to ignite the pilot.
- Allow the pilot to burn for three minutes, then measure thermopile output at the gas control terminals to confirm you see over 400 millivolts before returning the heater to normal service.
The Part You Need
| Part | Notes |
|---|---|
| Bradford White Pilot Assembly | Amazon | Match your water heater’s model and serial number from the rating plate on the tank. The correct pilot assembly varies by burner type and gas control version, so provide both numbers when ordering. |
When to Call a Pro
Bradford White recommends professional service for all gas system work, including pilot and burner assembly replacement. If you replace the pilot assembly and the problem continues, the manufacturer’s procedure directs you to replace the gas control valve next, which requires gas line disconnection, pressure testing, and combustion verification. A licensed technician has the meter to confirm thermopile millivolt output, the tools to safely handle gas connections, and the training to diagnose whether the gas control or another component is at fault. For any scenario where you smell gas, cannot relight the pilot after replacement, or lack experience with gas appliances, call a qualified service provider before proceeding. For gas line, burner, or igniter work, or if you ever smell gas, stop and call a licensed technician.