Rheem R802VA07542117MSA Error Code A111_F: One-hour Lockout: Main Limit Switch

What Does Code A111_F Mean?

Code A111_F on your Rheem R802VA07542117MSA is the one-hour lockout for the main limit switch. It is set after the main limit circuit has been open for more than 150 seconds — the dead-blower threshold — and after the overheat keeps recurring. The Bluetooth Communicating IFC cuts heating for a full hour to protect the heat exchanger and surrounding components from repeated overheating, and the alphanumeric LED blinks A111_F digit by digit with a pause between digits.

The airflow logic behind this code is the same as the rest of the main-limit family. This model uses a variable-speed, constant-CFM/PWM blower that is commanded to move a target airflow so the fixed heat from the burners is carried away and the limit stays closed. When the blower is not turning, heat builds on the heat exchanger, the limit will not reclose, and after the condition is sustained or repeated the control escalates all the way to this one-hour lockout. That persistence is why a failed blower motor, a failed blower capacitor, or a failed ECM module is the leading cause rather than a simple dirty filter.

A111_F is the top of the main-limit escalation ladder on this board. Its milder relatives are code T022_F, the troubleshooting-level warning that the limit opened on an overheat, and code A022_F, the alarm-level dead-blower fault set when the limit stays open more than 150 seconds; A111_F is where those conditions end up when they keep repeating. It differs from code A061_F, which is the blower-motor-cannot-run hard lockout declared after four dead-blower events: A111_F is reached through the main limit switch staying open, while A061_F is specifically the motor failing to run. Because the leading cause is unsafe to service, the only homeowner action is ruling out an extremely dirty filter; the blower and limit circuit belong to a technician.

What You'll Notice

• The furnace stops heating for about an hour and will not respond to the thermostat during that time
• The blower motor does not run when the furnace calls for heat
• The alphanumeric LED blinks out "A111_F" digit by digit with a pause between digits
• Repeated overheat shutdowns occurred earlier, before the one-hour lockout latched
• Little or no air comes from the supply registers

Common Causes

How This Is Diagnosed

Because the most likely cause is unsafe to service, this is primarily a technician diagnosis and the homeowner step below is limited to ruling out an extremely dirty filter. A technician checks whether the variable-speed blower motor runs on command, tests the blower capacitor and ECM module, inspects the wiring between the control board and the motor, and confirms that the limit recloses once airflow is restored. An extremely dirty filter is ruled out first because it is the only contributor a homeowner can safely correct.

How to Fix It: Rule Out an Extremely Dirty Air Filter (Blower Repairs Are Pro-Only)

What You'll Need

• New furnace filter (correct size) 🛒 Find at FiltersFast · 🛒 Find at Amazon
• Flashlight

Steps

1. Turn off electrical power at the breaker or switch AND shut off the gas supply Flip the furnace circuit breaker to OFF, or use the dedicated power switch on or near the furnace, then turn the manual gas shutoff valve to OFF (handle perpendicular to the pipe). If you smell gas, leave immediately and call your gas company. Do not continue until the gas smell is gone.
2. Inspect the filter for extreme clogging Slide the filter out and hold it up to a light. A fully matted, light-blocking filter can restrict enough airflow to keep tripping the limit, so this is the one cause a homeowner can safely address. If the filter is clean or was changed recently, note that, because it points more strongly to the blower motor.
3. Replace the filter only if it is heavily clogged Install a new filter of the correct size with the airflow arrow pointing toward the blower. Do not open, spin, test, or attempt to service the blower motor, its capacitor, or the ECM module; those repairs involve stored electrical charge and are for a technician.
4. Restore power and gas and watch whether the blower runs after the lockout clears Turn the gas valve to ON and restore power. Wait for the one-hour lockout to expire, or cycle power off for about 30 seconds and back on, then set the thermostat to call for heat. Listen and feel for the blower: strong airflow means the filter was the issue, while silence points to a failed blower motor that needs a professional.

When to Call a Professional

Contact a licensed HVAC technician if:

• The blower motor does not run when the furnace calls for heat
• A clean or newly installed filter does not stop A111_F from returning
• The furnace locks out for an hour repeatedly
• You hear humming or clicking from the blower but it will not spin, suggesting a capacitor or motor fault
• Any blower motor, capacitor, ECM module, wiring, or limit-switch service is needed

✓ Verified against manufacturer service manual — March 2026