Rheem Error Code A008: Exhaust Temperature High
Warning: Your Rheem HVAC system has detected an unusually high exhaust temperature, which could lead to system damage if not addressed.
How to Fix Rheem Code A008
- Check if the outdoor unit is clear of debris and has adequate airflow
- Inspect the exhaust vent for any blockages or obstructions
- If the problem persists, contact a professional HVAC technician
How to Reset Rheem Code A008
- Turn off the unit using the power button on the front panel.
- Turn off the gas supply valve.
- Turn off the circuit breaker supplying power to the unit. Wait 30 seconds.
- Restore power at the breaker, then open the gas valve.
- Turn the unit back on. If the error returns, the underlying issue needs repair.
Resetting clears the code from the display but does not fix the underlying fault. If the code returns after reset, proceed to the diagnostic steps above.
What Does Rheem Error Code A008 Mean?
The A008 error code on your Rheem HVAC system indicates that the exhaust temperature has exceeded the safe limit. This could be due to a variety of reasons, including a faulty temperature sensor, a clogged exhaust vent, or a problem with the heat exchanger. It's important to address this issue promptly to prevent further damage to your system.
Common Causes
- Faulty exhaust temperature sensor
- Clogged or blocked exhaust vent
- Problem with the heat exchanger
- Issues with the system's airflow
Diagnostic Steps
| If... | Check | Expected |
|---|---|---|
| System is running | Exhaust temperature using a thermometer | Below 200°F (93°C) |
| Exhaust temperature is high | Exhaust vent for blockages | Clear and unobstructed |
Applicable Rheem Models
- NCB(gas)
- NPE(electric)
- R801T(gas)
- R92E(electric)
- R92V(gas)
- RGE(gas)
- RH2T(electric)
- RNC(dual_fuel)
- RNE(electric)
- RNG(gas)
- RP16(electric)
- RPB(gas)
- RTGH(gas)
- Rheem Classic(gas)
- Rheem Classic 80 Plus(gas)
- Rheem Classic 80% Gas Furnace(gas)
- Rheem Classic 90 Plus(gas)
- Rheem Classic Plus Series(gas)
- Rheem Classic Series(dual_fuel)
- Rheem Prestige(gas)
- Rheem Prestige 95% Gas Furnace(gas)
- Rheem Prestige Series(gas)
Replacement Parts
| Part | OEM Number | Est. Cost | Where to Buy |
|---|---|---|---|
| Exhaust Temperature Sensor | RHEEM 4413785 | — | Find Part |
| Exhaust Vent | — | — | — |
Related Codes on Same Models
Other codes that affect the same Rheem model families as A008.
| Code | Description | Severity |
|---|---|---|
| A001 | Ignition Failure | Warning |
| A003 | Abnormal Ignition | Warning |
| A004 | False Flame Detection | Warning |
| A011 | No Flame Detected | Warning |
| A021 | Over-Temperature | 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 |