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

What Does Code A114_F Mean?

A114_F is a status code that tells you the Ruud U802VA's Bluetooth Communicating IFC has gone into a one-hour lockout because of repeated flame loss. The root event is the A013_F condition (Flame Lost after Established, active): the burner was proven lit, but the rectified flame-current signal from the sensor rod dropped out five times within one heat call. On the fifth loss, instead of relighting again, the control stops and reports A114_F to show the lockout is active.

During an A114_F lockout the furnace goes quiet and will not answer the thermostat for up to an hour — no relight attempts, no heat. This differs from a furnace that never lit: with A114_F the burners were lighting fine each time, they just would not stay confirmed. The one-hour hold exists so the control is not endlessly relighting a burner whose flame it cannot reliably prove. When the hour is up, the control automatically releases the lockout and starts a fresh heat cycle. If the same flame-loss problem is still present, it will lose flame five more times and drop back into A114_F, so the lockout can appear to repeat until the cause is corrected.

For a homeowner the important distinction is that ending the lockout is not the same as fixing it. Cycling power clears A114_F early, but if the flame sensor rod is still contaminated — the most common DIY-fixable cause of repeated flame loss — the next cycle simply loses flame again and re-locks out. Cleaning the rod addresses that root cause and is what prevents re-lockout. Note that A114_F is the flame-loss lockout; the parallel lockout for the burner never lighting at all is A113_F, driven by the A011_F ignition-failure condition. A014_F and A127_F are different again — those are flame-present-with-gas-valve-off safety alarms, not flame-loss faults.

What You'll Notice

• The furnace is idle and will not respond to the thermostat for about an hour after the lockout trips
• During the cycles leading up to the lockout, you may hear the burners cut out and relight several times
• The contractor app shows A114_F as the active lockout status, often after earlier T013_F or A013_F entries
• Heat delivery is interrupted and the house drifts below the setpoint while the lockout is active
• About once an hour the furnace may retry, lose flame again, and go quiet

Common Causes

How This Is Diagnosed

Because A114_F shares the A013_F root cause, diagnosis targets flame stability. The flame sensor rod is cleaned first, since a contaminated rod holding its microamp reading near the detection threshold is the most common and cheapest cause of repeated dropouts — this is the homeowner-safe step. The furnace is then watched over several cycles to confirm the flame holds.

If losses continue with a clean rod, a technician measures the steady-state flame current in microamps, inspects the burners for a lazy or wavering flame, and checks gas manifold pressure for a supply that sags mid-run. Those burner and gas-pressure checks are professional work and are not DIY on this furnace.

How to Fix It: Clean the Flame Sensor to Prevent Re-Lockout

What You'll Need

• Scotch-Brite pad
• 1/4-inch nut driver or small socket set
• Flashlight

Steps

1. Shut off power and gas before you touch anything Turn off power to the Ruud U802VA at the breaker or the furnace power switch, and shut off the gas supply at the manual shutoff valve on the gas line to the furnace. Confirm the furnace is fully off before opening any panel. If you smell gas, leave immediately and call your gas company.
2. Locate and remove the flame sensor Remove the burner-compartment door. The flame sensor is a single metal rod with a white porcelain base, mounted at the end of the burner assembly opposite the igniter, with one wire running to it. Note the wire routing, disconnect the wire, and remove the single retaining screw so you can lift the rod out.
3. Clean the sensor rod Gently clean the flame sensor rod with a Scotch-Brite pad until the metal is dull-bright. Ruud'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.
4. Reinstall and reconnect Set the rod back in its original position, reinstall the retaining screw, and reconnect the sensor wire exactly as it was routed. Make sure the rod does not touch the burner or any metal bracket. Refit the burner door.

When to Call a Professional

Contact a licensed HVAC technician if:

• A114_F returns after the flame sensor has been cleaned
• The flame sensor rod is visibly pitted or corroded, or the white porcelain base is cracked
• The burner flame looks yellow, lazy, or wavers rather than burning steady blue
• The lockout keeps repeating on an hourly rhythm despite clearing it
• Other gas appliances are also affected, suggesting a gas supply or pressure problem

✓ Verified against manufacturer service manual — March 2026