Rheem Error Code A021: Over-Temperature

Severity
Warning
Type
digital display
Where to look
front panel
Estimated repair cost: $300 — $650 (parts + labor)
Warning: Your Rheem HVAC system has detected an overheating condition. Turn off the system and call a professional for repair.

How to Fix Rheem Code A021

  1. Turn off the system at the thermostat and at the circuit breaker
  2. Do not attempt to open the unit or perform any repairs yourself
  3. Contact a licensed HVAC technician for diagnosis and repair

How to Reset Rheem Code A021

  1. Turn off the unit using the power button on the front panel.
  2. Turn off the gas supply valve.
  3. Turn off the circuit breaker supplying power to the unit. Wait 30 seconds.
  4. Restore power at the breaker, then open the gas valve.
  5. Turn the unit back on. If the error returns, the underlying issue needs repair.

What does A021 mean?

The A021 error code on your Rheem HVAC system indicates that the unit has reached an unsafe temperature. This is likely due to a malfunction in the system's temperature control or a problem with the cooling components. The system has automatically shut down to prevent damage or safety hazards. It's important to address this issue promptly to avoid further damage or potential safety risks.

Affected Models

Replacement Parts

PartOEM NumberEst. Cost
Temperature Control Board RHEEM 4505229 —
Compressor RHEEM 4502775 —
Refrigerant — —

Related Codes on Same Models

CodeDescriptionSeverity
A001 Ignition Failure Warning
A003 Abnormal Ignition Warning
A004 False Flame Detection Warning
A008 Exhaust Temperature High Warning
A011 No Flame Detected Warning
A031 Inlet Thermistor Open/Short Warning
A041 Outlet Thermistor Open/Short Warning
A043 Water Level Error Warning
A051 Fan Motor Abnormality Warning
A052 Fan Motor Speed Error Warning