Rheem Error Code 11: Rheem Code 11 - No Ignition
How to Fix Rheem Code 11
- Step 1: Ensure the gas supply to the unit is turned on. Check the shut-off valve on the gas line leading to the water heater.
- Step 2: Reset the unit by turning it off and then back on. See if the error clears. If it returns, do not continue to reset it.
- Step 3: Call a qualified HVAC technician or plumber to diagnose and repair the problem. Do not attempt to troubleshoot gas-related issues yourself.
How to Reset Rheem Code 11
- 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 11 Mean?
Rheem error code 11 signals that your tankless water heater attempted to ignite the burner but failed. This means the unit went through its startup sequence, including the fan starting and the igniter sparking, but the main burner flame didn't establish itself. The water heater will typically try a few times before locking out on this error. This is a critical safety issue because unburned gas can accumulate, creating a risk of explosion or carbon monoxide poisoning. It's important to address this problem right away to ensure your safety and the proper operation of your water heater.
Common Causes
- Gas supply issues (gas valve closed, low gas pressure)
- Faulty or dirty flame sensor
- Igniter failure
- Blocked or restricted vent system
- Defective gas valve
Diagnostic Steps
| If... | Check | Expected |
|---|---|---|
| Unit displays code 11 during startup | Check gas supply pressure at the unit's gas valve | Normal gas pressure (typically 5-10" WC for natural gas, 10-13" WC for propane) |
| Gas pressure is within range | Inspect the flame sensor for proper placement and cleanliness | Flame sensor is clean, properly positioned in the flame, and shows no signs of damage |
| Flame sensor is clean and positioned correctly | Measure the flame rectification signal (DC microamps) when the unit attempts to ignite | A stable DC microamp signal (typically 2-5 uA or as specified by Rheem) |
| No flame rectification signal | Test the igniter for continuity | Continuity exists across the igniter terminals (specific resistance value depends on the igniter model) |
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 | AP14914 | — | Find Part |
| Igniter | AP14838 | — | Find Part |
| Gas Valve | — | — | — |
Related Codes on Same Models
Other codes that affect the same Rheem model families as 11.
| Code | Description | Severity |
|---|---|---|
| A001 | Ignition Failure | Warning |
| A003 | Abnormal Ignition | Warning |
| A004 | False Flame Detection | 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 |