Rheem Error Code A004: False Flame Detection
Warning: Your Rheem furnace has detected a false flame, which could lead to system damage if not addressed.
How to Fix Rheem Code A004
- Step 1: Turn off the furnace at the thermostat and the power switch on the furnace.
- Step 2: Wait 30 seconds, then turn the power switch back on. If the furnace comes on and the error code is gone, the issue might be resolved. If not, proceed to the next step.
- Step 3: Call a professional HVAC technician. Do not attempt to open the furnace or tamper with any internal components.
How to Reset Rheem Code A004
- 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 A004 Mean?
The A004 error on your Rheem furnace indicates a false flame detection issue. This means the system's flame sensor has detected a flame when there shouldn't be one, causing the furnace to shut down to prevent potential damage. This is a safety feature, but it's important to address the underlying cause to restore proper function.
Common Causes
- Dirty or faulty flame sensor
- Incorrect gas pressure
- Electrical issues in the ignition system
- Clogged or damaged inducer fan
Diagnostic Steps
| If... | Check | Expected |
|---|---|---|
| Furnace is not running | Gas valve - should be closed | Closed |
| Furnace is running | Flame sensor - clean and inspect for damage | Clean and undamaged |
| Inducer fan is running | Fan speed - should be within manufacturer's specified range | Within specified range |
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 |
|---|---|---|---|
| Flame Sensor | RHE-4800100 | — | Find Part |
| Inducer Fan | RHE-4800200 | — | Find Part |
Related Codes on Same Models
Other codes that affect the same Rheem model families as A004.
| Code | Description | Severity |
|---|---|---|
| A001 | Ignition Failure | Warning |
| A003 | Abnormal Ignition | Warning |
| A008 | Exhaust Temperature High | 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 |