What does Rheem error code F2 mean on a heat pump?

F2 on Rheem heat pumps indicates an outdoor air temperature sensor fault. The NTC sensor reading is out of range. Check the sensor resistance: at 25°C it should read 10kΩ. Inspect the sensor for physical damage and check the wiring harness connector for corrosion or loose contacts. Replace the sensor if it reads OL or near zero resistance.

How do I reset a Rheem furnace after a fault condition?

Rheem furnaces with a 2-flash or higher fault code require diagnosing and resolving the root cause before reset. For a simple thermostat or power interruption reset: turn the thermostat to OFF, turn the furnace power switch off for 30 seconds, then restore power and turn the thermostat back on. If the fault recurs immediately, the underlying condition has not been resolved.

What causes a Rheem heat pump to run continuously without reaching setpoint?

A Rheem heat pump running continuously without reaching setpoint usually indicates low refrigerant charge (check for leaks and weigh in correct charge), a defrost control fault allowing frost accumulation on the outdoor coil, or a reversing valve stuck partially in mid-position (causes mixing of hot and cold gas). Check outdoor coil temperature and compare to expected saturated suction temperature at the current outdoor ambient.

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By Octavian Ghindea

Co-founder & CTO · Reviewed May 2026

What error codes does Rheem display?

Outdoor air temperature sensor fault

Indoor coil temperature sensor fault

2 blinks

Pressure switch fault — check inducer and flue

4 blinks

High limit switch open — check airflow

Common questions about Rheem equipment

What other HVAC brands does AskWhiz cover?

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