Rheem R802VA07542117MSA Error Code A022_F: Main Limit Switch Open

What Does Code A022_F Mean?

The main high-temperature limit switch on your Rheem R802VA07542117MSA opens whenever the heat exchanger overheats. On a brief trip the control logs the troubleshooting-level code T022_F. A022_F is the escalated, alarm-level version: it is set when that limit circuit stays open for more than 150 seconds continuously. When the limit will not reclose for that long, the Bluetooth Communicating IFC concludes that no air is moving through the cabinet at all — a dead-blower condition — because if the blower were running, it would eventually pull enough air across the heat exchanger to cool it and let the limit close again.

The reason this code usually means a failed blower is built into how the furnace proves airflow. This model uses a variable-speed, constant-CFM/PWM blower that is commanded to move a target airflow, and the control expects the limit to reclose within seconds as that air cools the heat exchanger. If the limit stays open past 150 seconds, air is not moving even at commanded speed, which points to a blower motor that is not turning, a failed blower capacitor, or a failed ECM module rather than a merely dirty filter. Because it is a two-stage design, the heat exchanger keeps producing heat during that window, so the alarm and lockout exist to stop the gas before damage occurs. The one cause a homeowner can safely check is a severely clogged air filter, which in combination with a weak motor can choke airflow badly enough to hold the limit open.

A022_F sits in the middle of the main-limit escalation ladder. Its milder counterpart is code T022_F, the troubleshooting-level limit-open warning tied to restricted airflow. If the dead-blower condition keeps recurring, the furnace latches code A111_F, the one-hour lockout for the main limit switch. All three differ from code A061_F: A061_F is specifically the blower-motor-cannot-run hard lockout the control declares after four dead-blower events, whereas A022_F and A111_F are reached through the main limit switch staying open. Because the leading cause here is unsafe blower work, the only step a homeowner should take is ruling out a severely clogged filter; everything else belongs to a technician.

What You'll Notice

• No warm air, and the blower does not appear to run at all when the thermostat calls for heat
• The furnace runs briefly, then shuts down and holds a lockout for about an hour
• The alphanumeric LED blinks out "A022_F" digit by digit with a pause between digits
• The blower motor stays silent while, or just after, the burners were lit
• A hot or faintly burning smell from heat that was trapped on the heat exchanger earlier in the cycle

Common Causes

How This Is Diagnosed

Because A022_F is treated as a dead-blower condition, the one thing a homeowner can safely check is whether the air filter is so severely clogged that it is choking airflow — pull it and replace it if it is matted or blocks light. If the filter is clean and the code still locks out, the problem is the blower itself. A technician will confirm whether the variable-speed motor is receiving its command and power, test the run capacitor and ECM module, and check the wiring between the control board and the motor before deciding whether the motor or its module must be replaced. That motor-level work is not a homeowner job.

How to Fix It: Check for a Severely Clogged 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 severe clogging Slide the filter out of the return duct or blower slot and hold it up to a light. A completely matted, light-blocking filter can restrict enough air to hold the limit open, so this is the one homeowner-correctable cause worth ruling out. If the filter is clean or was recently changed, note that, because it points more strongly to the blower motor.
3. Replace the filter only if it is heavily clogged If the filter is severely dirty, install a new one of the correct size with the airflow arrow pointing toward the blower. Do not attempt to open, spin, test, or service the blower motor, capacitor, or ECM module yourself; those repairs involve stored electrical charge and are for a technician.
4. Confirm every supply and return register is open Walk the house and make sure supply registers and return grilles are fully open and not blocked by rugs, furniture, or closed dampers, since severe register blockage can add to the airflow restriction. Do not open the blower compartment to work on the motor.
5. Restore gas and power and watch whether the blower runs Turn the gas valve back to ON and restore power, then set the thermostat to call for heat. Cycle power off for about 30 seconds and back on if needed to clear the lockout. Listen and feel for the blower: strong, steady airflow means the filter was the issue; silence or no airflow means the blower motor needs a professional.

When to Call a Professional

Contact a licensed HVAC technician if:

• The blower motor does not spin at all when the furnace calls for heat
• The filter is clean or newly replaced but A022_F returns, which points to the blower motor, capacitor, or ECM module
• You hear a hum or a click from the blower but it does not turn
• The furnace repeatedly locks out, escalating to the one-hour lockout A111_F or the hard lockout A061_F
• Any suspected blower motor, capacitor, ECM module, wiring, or limit-switch work is needed

✓ Verified against manufacturer service manual — March 2026