Home Fault Codes

A. O. Smith Water Heater 4 Flashes: Meaning and Fix

Applies to: A. O. Smith residential standard gas water heaters (series 300/301 FVIR models such as GCV, GVR and XCV, per Service Handbook 327726); power vent and electric lines use different controls.

4 Flashes
How 4 Flashes appears on a A. O. Smith water heater display.

Also shown as: Four Flashes

Reading the water heater display

A gas tank water heater reports its fault as a count of LED flashes on the gas control valve, seen through the small window or viewport near the base of the tank. Count the flashes, note the pause (usually three seconds) and watch a second full round before you decide which code it is. Some controls use two groups, such as six flashes then one.

A. O. Smith makes tank water heaters whose gas control valve has a status light that flashes a fault code, then pauses three seconds and repeats. The meaning depends on the control, so match the chart to your model series. Check the model label on your unit before using any chart.

What causes 4 Flashes

How to fix it

If you smell gas, leave the building and call your gas utility from outside; do not touch switches or the unit. Switch the water heater off and let it cool before you touch any internal part, and call a licensed plumber or water heater technician if you are not sure.

The code meaning comes from the manufacturer document listed under Sources. The causes and steps below are general troubleshooting guidance, not the manufacturer's service procedure.

  1. Turn the gas control knob to OFF. If you smell gas, leave the building and call your gas utility from outside; do not touch switches.
  2. Turn the main gas supply OFF as well.
  3. Have a technician replace the gas control valve/thermostat, which is A. O. Smith's listed repair.
  4. Do not relight the unit until the control has been replaced.
  5. If the code returns after these checks, call a licensed plumber or water heater technician and give them the flash count and the model number from the rating plate.

Questions

What does A. O. Smith water heater 4 Flashes mean?

4 Flashes on a A. O. Smith residential standard gas water heater (FVIR, status light on the gas control valve/thermostat) means the water temperature exceeded the limit and the energy cutoff (ECO) activated. A. O. Smith's fix is to turn the knob and main gas supply off and replace the gas control valve/thermostat. A. O. Smith repeats the flash, pauses three seconds, then repeats.

Can I reset the water heater myself?

Turning the gas control knob to OFF, waiting, and relighting it clears some codes. If the same flash count comes back, the fault is still there and the unit will lock out again. Do not bypass a safety device to keep it running.

When should I call a technician?

Call a licensed plumber or water heater technician for anything involving gas, venting, the pilot, the gas control or flammable vapor sensor, or when the code keeps returning after the simple checks.

Other brands with code 4 Flashes

The same code can mean something different on another maker's appliance. Check the brand before you act.

Bradford White water heaterHigh tank temperatureChamberlain garage door openerSensor beam misaligned (sender steady, receiver dim)Craftsman garage door openerSensor beam misaligned (sender steady, receiver dim)Goodman furnaceOpen limit switchLennox furnaceLow flame signal, check flame sensorLiftMaster garage door openerSensor beam misaligned (sender steady, receiver dim)Rheem water heaterThermal cutoff device trippedTrane furnaceOpen high limit device

Other A. O. Smith water heater codes

0 FlashesControl off or pilot out2 FlashesThermopile voltage low5 FlashesSensor failure7 FlashesInternal control failure8 FlashesPower off failure

Sources

Part numbers are OEM references; confirm fit by your model number before ordering. Meanings compiled from manufacturer and parts-retailer documentation; see sources below. Unplug the appliance before opening it.