Rheem R96VA0702317MSA Error Code 11: Failed Ignition

What Does Code 11 Mean?

Error code 11 on the Rheem R96V means the furnace attempted to ignite but could not confirm a flame. During a normal heating cycle, the inducer motor starts, the hot surface igniter glows, the gas valve opens, and the flame sensor checks for combustion. If the flame sensor cannot detect a flame, the control board shuts off the gas valve for safety.

After the first failed attempt, the furnace will automatically retry up to three more times. If all four ignition attempts fail consecutively, the furnace enters a one-hour safety lockout and alternates between displaying codes 11 and 10. During the lockout, heating is disabled but the furnace will automatically try again after the hour is up.

The most common cause is a dirty flame sensor rod with oxide buildup that prevents it from sensing the flame properly. The second most common cause is the gas supply being turned off at the manual shutoff valve near the furnace or at the meter. A faulty hot surface igniter or control board issue are also possible but less likely.

Common Causes

How to Fix It: Clean the Flame Sensor and Check Gas Supply

What You'll Need

• 1/4-inch nut driver or hex driver
• a Scotch-Brite pad
• Flashlight

Steps

1. Turn off electrical power at the breaker or power switch AND shut off the gas supply valve Locate the furnace circuit breaker and flip it to OFF, or use the power switch on or near the furnace. Turn the manual gas shutoff valve to the OFF position (perpendicular to the pipe). If you smell gas at any point, leave the house immediately and call your gas company from outside.
2. Locate the flame sensor Remove the furnace access panel and look near the burner assembly. The flame sensor is a thin metal rod (usually bent at an angle) with a porcelain insulator at its base. It has a single wire connected to it and is held in place by one 1/4-inch screw.
3. Remove the flame sensor Disconnect the wire from the flame sensor. Remove the mounting screw and carefully pull the sensor out. Handle it by the porcelain insulator or mounting bracket — avoid touching the rod with your fingers.
4. Clean the sensor rod Gently rub the metal rod with a Scotch-Brite pad until it is clean and shiny, removing all dark oxide buildup. Some HVAC professionals recommend using a Scotch-Brite pad as it leaves no abrasive residue. Do not bend the rod or damage the porcelain insulator.
5. Reinstall the flame sensor Place the sensor back in its bracket, secure the mounting screw, and reconnect the wire. Make sure the sensor rod will sit in the flame path when the burners ignite.
6. Verify the gas supply is on Check that the manual gas shutoff valve near the furnace is open (handle parallel to the pipe). Also confirm the gas meter valve is open if accessible.
7. Restore power and gas, then test Turn the gas supply valve to ON and restore electrical power. Set your thermostat to call for heat and observe the ignition sequence. If the furnace was in lockout, you may need to cycle power off for 30 seconds and back on to clear the lockout.

When to Call a Professional

Contact a licensed HVAC technician if:

• The burners still fail to stay lit after cleaning the flame sensor
• The hot surface igniter does not glow during the ignition sequence
• You can hear gas flowing but it does not ignite
• The flame appears yellow, lazy, or rolls out of the combustion chamber
• Code 11 recurs repeatedly even with a clean flame sensor and open gas supply

✓ Verified against manufacturer service manual — March 2026