How To Troubleshoot And Gas Water Heater That Doesn’t Heat

If a gas water heater fails to heat water at all, perform these diagnostics:

  • Be sure the gas to the water heater is turned on. Turn the gas control knob to PILOT to prevent the burner ignition when looking inside. Look to see if the small flame at the end of the pilot gas supply tube—are lit.
  • If the water heater’s pilot light has gone out, follow the instructions on the tank to relight it.
    It’s also possible that the gas inlet valve has been closed. If so, turn the handle parallel to the line and relight the pilot.
    If the pilot won’t light, the thermocouple may be defective call a water heater repair person to get replaced.

  • If the burner is not on, replace the cover and make sure the thermostat is set to about 120 degrees F.
  • If the burner ignites, replace the cover and turn the thermostat back to an appropriate setting. Otherwise have the water heater checked out by a water heater repair specialist.
  • If you smell a gas, turn the gas valve control to OFF.

Wait until the gas smell dissipates before relighting the pilot light. Otherwise, immediately turn off the gas supply valve, ventilate the space, and call a plumber from a remote location.