Rheem Error Code A003: Abnormal Ignition
Warning: Your Rheem HVAC system has encountered an abnormal ignition issue. It's safe to troubleshoot, but it's recommended to call a professional for repair.
How to Fix Rheem Code A003
- Step 1: Check if the gas valve is open and the gas supply is on.
- Step 2: Inspect the area around the furnace for any gas leaks. If you smell gas, evacuate immediately and call your gas company.
- Step 3: If no gas leak is detected, call a professional HVAC technician for repair.
How to Reset Rheem Code A003
- 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 A003 Mean?
The A003 error on your Rheem HVAC system indicates an abnormal ignition issue. This could mean that the system is having trouble igniting the burner or keeping it lit. This is likely due to a problem with the ignition system or the gas supply. Don't worry, it's safe to troubleshoot, but it's recommended to call a professional for repair.
Common Causes
- Faulty ignition control module
- Dirty or faulty igniter
- Gas supply issue (low pressure or leak)
- Clogged or damaged flame sensor
Diagnostic Steps
| If... | Check | Expected |
|---|---|---|
| Furnace won't turn on | Gas valve - is it open? | Open |
| Furnace turns on but doesn't ignite | Igniter - is it glowing? | Glows red hot |
| Furnace ignites but flame goes out | Flame sensor - is it clean and undamaged? | Clean and undamaged |
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 |
|---|---|---|---|
| Ignition Control Module | RHEEM 80-00012710 | — | Find Part |
| Igniter | RHEEM 80-00012700 | — | Find Part |
| Flame Sensor | RHEEM 80-00012720 | — | Find Part |
Related Codes on Same Models
Other codes that affect the same Rheem model families as A003.
| Code | Description | Severity |
|---|---|---|
| A001 | Ignition Failure | 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 |
| A053 | Fan Motor Open Circuit | Warning |
| A054 | Fan Motor Overcurrent | Warning |
| A055 | Fan Motor Locked | Warning |