Gas Water Heater Burner Not Lighting at All
On this page (5 sections)
The Short Answer: If a gas water heater shows no flame at all, with no pilot and no burner, the cause is usually upstream of the flame. Typical causes are a closed gas supply valve, an empty propane tank, the control turned to OFF or VACATION, a failed igniter, or a safety lockout that stops the control from opening the gas. Check supply and settings first, then follow the lighting label once.
Which problem do you have?
There are three different symptoms, and each has its own causes:
- Nothing lights at all: covered on this page.
- Pilot lights but goes out when you release the knob: see why won’t my gas water heater stay lit.
- Pilot stays lit but the main burner won’t come on, or lights and goes out: see pilot lit but burners won’t ignite and gas water heater burner won’t stay lit.
Causes of no flame
| What you notice | Likely cause | Next step |
|---|---|---|
| Other gas appliances also dead | Utility supply off, meter problem, or propane empty | Call the utility or propane supplier |
| Only the water heater; supply valve handle across the pipe | Supply valve closed | Open it (handle along the pipe), then follow the lighting label |
| Knob on OFF or VACATION, or dial at lowest | Control setting | Set per the label and relight |
| Piezo button clicks, no spark visible | Igniter, wire, or electrode fault | Service; see piezo igniter won’t spark |
| Spark visible, no pilot flame | No gas reaching the pilot: blocked pilot tube or orifice, or a control fault | Service |
| Status light flashing a fault code | Control lockout (vapor sensor, over-temperature, others) | Read the code; see blinking red light |
| Power-vent model, blower silent | No power or blower fault; the control won’t release gas | See blower not working |
| Heater just installed or gas was off for work | Air in the supply line | The installer or gas technician restores and purges the line |
Two causes catch people out. Flammable-vapor-resistant (FVIR) tanks have a safety that locks the heater out after vapors or overheating in the burner chamber. Power-vent heaters won’t release gas unless the blower runs and proves airflow.
What you can check safely
- Smell around the heater at floor level. If you smell gas, stop and leave.
- Check that the supply valve on the heater’s gas line is open and that other gas appliances work. If you use propane, check the tank gauge.
- Check the control knob position and temperature setting.
- Make sure no gasoline, paint, solvents, or cleaning chemicals are stored near the heater.
- Follow the lighting instructions on the heater’s label exactly, including the wait time after turning it off. Try once.
- If nothing lights, or you hear a bang, see a large yellow flame, or smell gas, turn the control to OFF and call for service.
Don’t hold the igniter button down repeatedly or keep cycling the control. If gas is flowing but not lighting, it can build up and ignite late with a bang.
What the technician will check
A gas technician confirms supply pressure at the heater against the rating plate and checks the igniter, electrode gap, and wiring. They also inspect the pilot tube and orifice for blockage. On FVIR models, they look at the flame arrestor and the vapor and temperature sensors, and find out why a lockout happened. If the gas control receives everything it needs and still won’t open, they replace it with one that matches the model and gas type, then leak-test and run the heater.
Frequently Asked Questions
Q: Is a bad thermocouple the reason nothing lights? A: Usually not. A thermocouple or thermopile can only hold a pilot that has already lit. If you never see a flame, the problem is gas supply, the igniter, or a lockout.
Q: My heater worked yesterday. Could it be air in the line? A: Unlikely. Air enters the line when the gas has been shut off or the heater was replaced. If the supply hasn’t been interrupted, look for another cause, and never loosen fittings to “bleed” a line yourself.
Manuals and supporting references
These links distinguish general safety information from model-specific documentation. A manual directory helps you locate your unit’s instructions; it does not establish that every model uses the same parts, codes, or test values.
- PG&E: recognizing and responding to a gas leak (opens in a new tab)Emergency actions for suspected fuel-gas leaks.
- CPSC: carbon monoxide fact sheet (opens in a new tab)Carbon monoxide hazards and emergency response.
Editorial standards and corrections · Prepare a useful service request