Bradford White Water Heater No Hot Water — What’s Happening
When your Bradford White water heater produces no hot water, the unit is failing to ignite the pilot or main burner, or the gas valve isn’t opening to allow fuel to the burner. The control board typically registers this as an ignition failure (Error Code 110) or a gas valve fault (flashing light patterns 7 or 8 on models with diagnostic lights). The system detects it cannot generate heat and shuts down as a safety measure.
The pilot may be out completely, or it may light but fail to keep the main burner running. In either case, the thermopile (the small voltage generator heated by the pilot flame) or the gas valve itself is usually at fault. Less commonly, blockages in the pilot tube or air intake prevent proper combustion.
Most Likely Causes
- Failed or weak thermopile The thermopile no longer generates enough voltage (below 0.35V) to signal the gas valve to stay open, causing the pilot to light but the main burner to never fire or to shut off immediately.
- Dirty or misaligned thermopile or pilot assembly Soot, corrosion, or debris on the thermopile tip prevents it from heating properly, or the pilot flame doesn’t touch the thermopile because the assembly has shifted out of position.
- Blocked pilot tube The small gas line feeding the pilot is clogged with dirt, spider webs, or other debris, preventing the pilot from igniting or staying lit.
- Faulty gas valve The gas valve coil is electrically open or shorted, or internal valve components have failed, preventing gas flow even when the thermopile voltage is adequate.
- Low gas supply pressure Insufficient gas pressure from the main line or a closed manual shutoff valve prevents the pilot and burner from receiving enough fuel to operate.
- Tripped high limit switch The water temperature exceeded the safety limit (usually due to a failed thermostat), causing the high limit switch to open and cut power to the gas valve.
- Corroded or loose wiring connections Electrical connections between the thermopile, gas valve, and control board are corroded or not making solid contact, interrupting the control circuit.
How to Diagnose and Fix
- Turn the gas control knob to OFF and wait 5 minutes to clear any residual gas from the combustion chamber.
- Turn the knob to PILOT and press and hold the red button while using a long lighter to ignite the pilot flame at the burner (if applicable to your model), or press the igniter button on electronic ignition models.
- Observe whether the pilot lights and stays lit after releasing the button, and whether the main burner fires when you turn the knob to ON or the temperature setting.
- Check the diagnostic light pattern on the control board (if equipped) and note the number of flashes to identify specific fault codes like 7, 8, or 110.
- Visually inspect the pilot assembly and thermopile for soot buildup, corrosion, or misalignment, and clean with a soft brush or compressed air if dirty.
- Disconnect the thermopile wire from the gas valve, set a multimeter to DC volts, and measure the voltage across the thermopile terminals while the pilot is lit (should read at least 0.35V to 0.75V).
- Test the gas valve by measuring voltage at the valve terminals with the thermopile connected and the pilot lit, then check for continuity across the valve coil with power off.
- Reset the high limit switch by pressing the red button on top of the water heater (usually located near the thermostat) and listen for a click, then attempt to relight the pilot.
Parts You Might Need
| Part | Notes |
|---|---|
| Thermopile | Amazon | Generates millivolt power to hold the gas valve open when heated by the pilot flame. |
| Gas Valve (Honeywell or White Rodgers) | Amazon | Controls gas flow to pilot and main burner, contains internal coil and safety shutoff. |
| Pilot Assembly Kit | Amazon | Includes pilot tube, orifice, thermopile, and bracket for complete replacement of ignition components. |
When to Call a Pro
Call a licensed plumber or gas technician for any work involving the gas valve, gas line connections, or burner assembly. Testing and replacing the thermopile can be done by a confident DIYer, but all gas appliance repairs carry risk of gas leaks or improper combustion. If you smell gas at any point, shut off the gas supply at the manual valve immediately and call a professional. If you’ve replaced the thermopile and cleaned the pilot assembly but still get ignition failure codes or no main burner operation, the gas valve or control board likely needs professional diagnosis and replacement. For gas line, burner, or igniter work, or if you ever smell gas, stop and call a licensed technician.