Rheem R96VA0702317MSA Error Code 11: Failed Ignition
What Does Code 11 Mean?
Error 11 appears on the Rheem R96V Integrated Furnace Control (IFC) after the very first failed ignition attempt of a heat cycle. Because this is a condensing, two-stage, variable-speed furnace, every heat call starts at high fire: the induced-draft motor pre-purges, the low and high pressure switches must close, the hot-surface igniter heats, the gas valve opens, and the flame sensor rod has to prove a flame within the trial-for-ignition window. If no flame current is detected, the IFC closes the gas valve and posts code 11.
Up to three failures are not treated as critical — the control keeps retrying. On the fourth consecutive failure the IFC drops into a one-hour lockout and alternates code 11 with code 10 (One-Hour Lockout) on its dual 7-segment display. During that hour, cooling and fan still work but heat is disabled until the furnace retries automatically.
The most common cause on this model is a dirty flame-sensor rod that has built up oxide and can no longer conduct the small flame-sensing current. The next most common is simply a gas supply that has been shut off at the manual valve. A weak or miswired hot-surface igniter, a faulty IFC, or flame failing to carry across all burners are less common. Note that a rod that only senses weakly first tends to post code 12 (Low Flame Sense) as an early warning, and a flame that lights then drops out is code 13 (Flame Lost After Established) — code 11 specifically means no flame was ever confirmed on the attempt.
What You'll Notice
- The furnace runs its startup sequence (you hear the inducer and see the igniter glow) but then shuts down without producing heat
- You feel little or no warm air even though the thermostat is calling for heat
- The IFC display shows a steady 11, or alternates 11 and 10 once it has locked out
- You may hear the gas valve click open followed by the system shutting off a few seconds later
- After four tries the furnace goes quiet for about an hour, then attempts to start again on its own
Common Causes
How to Fix It: Clean the Flame Sensor and Confirm the Gas Supply
What You'll Need
Steps
- Turn off power at the breaker or furnace switch AND shut off the gas supply Switch the furnace circuit breaker (or the service switch on the furnace) to OFF, then turn the manual gas shutoff valve perpendicular to the pipe. If you smell gas, leave immediately and call your gas company.
- Locate the flame sensor Remove the burner-compartment access panel. The flame sensor is a single thin metal rod with a white porcelain base and one wire, mounted at the far end of the burner assembly opposite the igniter.
- Remove the sensor Unplug the sensor wire, remove the single 1/4-inch mounting screw, and slide the rod out. Handle it by the porcelain base.
- Clean the rod Gently clean the flame sensor rod with a Scotch-Brite pad until the metal is dull-bright. Rheem's guide lists fine steel wool as the cleaning material, but many HVAC technicians prefer a Scotch-Brite pad because it leaves no abrasive residue on the rod. Do not clean or scratch the white porcelain base, and take care not to bend the rod.
- Reinstall the sensor and confirm gas is on Refit the rod so it will sit in the burner flame path, secure the screw, and reconnect the wire. Return the manual gas shutoff valve to the open position (handle parallel to the pipe).
- Restore power and test Turn the power back on and set the thermostat to call for heat. If the furnace was in lockout, it may take up to an hour to retry, or you can cut power for 30 seconds to clear the lockout and retry immediately.
When to Call a Professional
Contact a licensed HVAC technician if:
- The burners still will not stay lit after the flame sensor is cleaned and the gas supply is confirmed open
- The hot-surface igniter never glows during the startup sequence
- You hear gas flowing but it never ignites
- Code 11 keeps returning and the furnace repeatedly drops into the code 10 one-hour lockout
- The flame looks yellow or lazy or appears to roll out toward the front of the burners
Frequently Asked Questions
Why does my R96V keep showing 11 and 10 together?
Alternating 11 and 10 means the furnace failed to ignite four times in a row and has entered a one-hour safety lockout. It will retry automatically after the hour, but the underlying ignition problem should be resolved so it does not keep recurring.
Can I just reset the furnace to clear code 11?
Cutting power for about 30 seconds clears the lockout, but if the cause (a dirty flame sensor or closed gas valve) is not fixed, the code will come right back on the next heat call.
How often does the flame sensor need cleaning?
It varies by home and air quality, but many furnaces benefit from a flame-sensor cleaning roughly once a heating season as part of routine maintenance. Homes with more dust or combustion residue may need it more often.
✓ Verified against manufacturer service manual — March 2026