Flashing Green Light on a Water Heater: What It Means

The Short Answer: On most gas water heaters with an electronic gas control, one short flash every three or four seconds is the normal “all is well” signal: the pilot is lit or the heater is idle at temperature. A fast flicker usually means it is heating. Two or more flashes in a group, followed by a pause, is a fault code whose meaning depends on the brand and control.

Normal patterns

Most of these status lights sit on the gas control (the box with the temperature knob) of a gas tank heater, or on the control panel of a power-vent model. The documented normal patterns for controls we have checked:

Sources: Bradford White guide 238-55948 (opens in a new tab), Bradford White guide 238-55968 (opens in a new tab), Rheem TB 1627 (opens in a new tab).

A. O. Smith, State and other brands that use similar electronic gas controls also describe one flash every few seconds as normal operation, but check the label on your heater, because LED color and timing vary by control.

When the light is a fault code

A fault code is a group of flashes, a longer pause, then the same group again. Count two full cycles. Some power-vent controls add a second short group after the first (for example six flashes, then two).

Fault meanings are not shared across brands. Four flashes is a high-temperature shutdown on the Bradford White and Rheem controls above, but five flashes means different things on Bradford White atmospheric and power-vent models. Look up your count on the label or in the manual for your model, or use these pages:

• Status light blinking 3 times
• 5 flashes on a water heater
• Status light blinking 6 times

Quick checks that tell you a lot

• Is the water hot? A single slow flash with normal hot water needs no action.
• Did the light change after something happened? A power outage, a gas shutoff, a heater that was just drained, or heavy snow on a power-vent termination all point the technician in a direction. Write it down.
• No light at all? On an atmospheric heater, a dark status light usually means the pilot is out; follow the lighting instructions on the heater’s label. On a power-vent heater, check that it is plugged in and the breaker is on.

Electric tank heaters and tankless heaters are different. Most standard electric tanks have no flashing status light, and tankless units show numbered codes on a display. Use the manual for those models rather than the gas-control patterns above.

Frequently Asked Questions

Q: The light flashes once every few seconds but I have no hot water. What does that mean? A: On an ICON atmospheric control, one flash means the pilot is lit and the control is not calling for heat. If the water is cold, the temperature setting may be very low, or a hot-water fixture or mixing valve may be the problem. If the burner never comes on with the dial turned up, have the control checked.

Q: Should I reset the heater when the green light flashes? A: Not for the normal one-flash pattern. Reset only applies to a fault code, and only once after the cause is understood. If the same fault returns, leave the heater off and arrange service.

Q: Why does my green light stay on solid? A: On Bradford White ICON atmospheric controls, a steady light means the knob was just turned to OFF and the control is shutting down. Wait until the light goes out before relighting, as the lighting label instructs.