Ruud U802VA050317MSA Error Code A114_F: One-hour Lockout: Flame Lost Failure

What Does Code A114_F Mean?

Code A114_F on the Ruud U802VA indicates a one-hour lockout triggered by repeated flame loss. The furnace successfully lit the burners, but the flame went out five times during a single heat call, so the Integrated Furnace Control locked out to prevent continuous cycling. This is the lockout status for the flame-loss condition (related to codes T013_F and A013_F).

The flame sensor continuously monitors the burner flame during operation. When the sensor cannot maintain a consistent reading — due to contamination, corrosion, or a failing sensor — the control intermittently loses confirmation that the flame exists and shuts off the gas valve as a safety measure. Each restart consumes one of the five allowed attempts.

A dirty or oxidized flame sensor is the most common cause by far. The thin metal rod accumulates a coating over time that insulates it from the flame's ionization current. Low gas pressure or a drafty combustion chamber can also cause the flame to physically go out, but these are less common than a contaminated sensor.

Common Causes

How to Fix It: Clean the Flame Sensor

What You'll Need

• Scotch-Brite pad
• 1/4-inch hex-head nut driver or screwdriver
• Flashlight
• Clean cloth or paper towel

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 gas shutoff valve to the OFF position (perpendicular to the pipe). If you smell gas at any point, leave the area immediately and call your gas company.
2. Open the furnace access panel and locate the flame sensor Remove the furnace's front access panel. The flame sensor is a thin metal rod with a porcelain insulator base, mounted near the burners with a single screw. It extends into the path of the burner flames.
3. Remove and clean the flame sensor Disconnect the wire connector from the sensor and remove the mounting screw. Gently rub the metal rod with a Scotch-Brite pad until it appears clean and shiny. Do not use steel wool, as it can leave metal fibers on the porcelain insulator. Wipe the rod clean with a cloth.
4. Inspect the sensor for damage Check the metal rod for severe pitting or thinning, and the porcelain insulator for cracks. If the rod is severely corroded or the porcelain is cracked, the sensor needs replacement — cleaning will not restore a physically damaged sensor.
5. Reinstall the flame sensor and close the panel Reattach the flame sensor with the mounting screw and reconnect the wire connector. Ensure the rod is properly positioned in the burner flame path. Replace the access panel.
6. Restore gas and power, then test Turn the gas supply valve to ON and restore electrical power. Cycle the power (off for 30 seconds, then back on) to clear the lockout. Set the thermostat to call for heat and monitor the furnace through several complete heating cycles to confirm the flame stays lit throughout.

When to Call a Professional

Contact a licensed HVAC technician if:

• Code A114_F returns after cleaning the flame sensor
• The flame sensor rod is visibly pitted, thinned, or the porcelain insulator is cracked
• The burner flames appear yellow, uneven, or waver during operation
• Other gas appliances are also having issues (possible gas supply problem)
• You notice a gas odor near the furnace (leave immediately and call your gas company first)
• The problem keeps recurring even with a clean flame sensor

✓ Verified against manufacturer service manual — March 2026