Rheem Water Heater 7 flashes: Flammable vapor sensor lockout (error 47)
Updated October 2026 · Sourced from Rheem documentation
Seven flashes followed by a three second pause. The bulletin says the flammable vapor sensor detected gasoline or other hydrocarbon vapors, so the control shut off all outputs and went into hard lockout.
Is it safe to keep running? No. Turn it off and get it checked. Call a qualified technician. The bulletin lists checking for flammable vapors and sensor resistance, and the lockout only clears under specific conditions.
7 flashes at a glance
| Code / how it shows | Meaning | Applies to |
|---|---|---|
| 7 flashes Gas valve status light: seven flashes, then a three second pause. Display models show 47. | Flammable vapor sensor lockout (error 47) | Rheem PowerVent ESII gas tank water heaters with Honeywell electronic gas control (gas valve status light flash codes, and display codes on electronic control models) |
Check this first
Only steps a homeowner can do safely. Do not open electrical panels or the burner area.
- Move gasoline, paint thinners and other flammable liquids and vapors away from the water heater area and ventilate the room.
- If you smell gas or fumes, do not touch switches, leave the building and call your gas supplier or the fire department from outside.
🛑 Stop and call a licensed pro if
- Call a qualified technician. The bulletin lists checking for flammable vapors and sensor resistance, and the lockout only clears under specific conditions.
- You smell gas. Leave the house, do not touch switches, and call your gas utility from outside.
- Codes for flame failure, overheating, venting or the control board that return after one reset.
- Water leaking from the heater, the relief valve discharging, or scorching around the burner area.
- A carbon monoxide alarm sounds. Get everyone outside and call 911 or the fire department.
Safe first steps for any Rheem code
- Write down the exact code shown on the controller or the number of status light flashes.
- Turn the water heater power off and back on (or press the reset button the manual describes) once. If the code comes back, stop resetting.
- Make sure the gas supply valve to the heater is open and other gas appliances in the home are working.
- Make sure the cold water supply valve is fully open and hot water taps are not partly closed.
- Look at the outside vent terminal for snow, ice, leaves or anything blocking it (look only).
Source: Rheem Technical Service Bulletin 1627, PowerVent with Honeywell Electronic Control, p. 6. Codes are series-specific, so your unit's own manual is the final word. Reviewed October 2026.
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