Rheem uses different error code conventions across product families. Tankless (RTGH series) uses two-digit codes; hybrid heat pump (ProTerra) uses alphanumeric (A1, P5, etc.); condensing power-vent tanks use C-codes; smart EcoNet-equipped units push error messages to the app. This page covers the most common codes across all families.
RTGH gas tankless error codes
| Code | Meaning | Fix |
|---|---|---|
| 11 | No ignition | Gas supply off, propane tank empty, gas valve closed, or pilot/ignition failure. Verify gas supply first. |
| 12 | Flame failure during operation | Often debris in the burner air intake — clean intake filter and check vent termination for blockage. |
| 13 | Combustion control fault | Combustion air adjustment is off — typically requires service technician to recalibrate. |
| 14 | High-temperature shutoff (heat exchanger) | Scale buildup on the heat exchanger — descale immediately. Recurring code 14 indicates HX damage; warranty claim. |
| 15 | Thermistor (temperature sensor) fault | Sensor wire disconnected or sensor failed. Reconnect at the control board; if persistent, replace sensor. |
| 16 | Outlet temperature too high | Set point too high, or scale on HX reducing heat transfer. Lower setpoint and descale. |
| 29 | Neutralizer fault | Acidic condensate not being neutralized — refill or replace the condensate neutralizer cartridge. |
| 31 | Inlet thermistor fault | Cold-water-inlet temperature sensor failed. Replace sensor. |
| 32 | Outlet thermistor fault | Hot-water-outlet temperature sensor failed. Replace. |
| 61 | Combustion fan fault | Power-vent or combustion fan failure. Check for obstruction in the fan; replace if motor seized. |
| 71 | Gas solenoid fault | Gas modulation valve failure. Often warranty-covered — call Rheem. |
| 76 | Remote control communication error | Wire to wall remote disconnected, or remote module failed. Reconnect or replace remote. |
| 90 | Combustion abnormal | Vent blockage or insufficient combustion air. Clean vent termination and verify air supply. |
| 92 | Neutralizer life expiring | Soft alert — replace condensate neutralizer within 30 days. |
ProTerra (hybrid heat pump) error codes
| Code | Meaning | Fix |
|---|---|---|
| A1, A2 | Heat pump anti-frost / defrost cycle | Normal during cold ambient — no action needed unless persistent. |
| P1 | Hot side temperature sensor fault | Replace upper tank temperature sensor. |
| P2 | Cold side temperature sensor fault | Replace lower tank temperature sensor. |
| P3 | Evaporator temperature sensor fault | Service technician — refrigerant-system diagnostic. |
| P5 | Heat pump compressor over-temperature | Ambient air too warm or airflow restricted — clean air filter on front panel. |
| F1, F2 | Element fault (upper / lower) | Element failed or wiring disconnected. Test resistance and replace if open. |
| F3 | Thermostat fault | Replace thermostat assembly. |
| L1 | Leak detection alarm | EcoNet detected water on the floor sensor — check around the tank base immediately. |
Performance Platinum condensing gas tank error codes
| Code | Meaning | Fix |
|---|---|---|
| C1 | Combustion blower fault | Inducer motor failed or pressure switch tubing disconnected. Verify tubing first. |
| C2 | Pressure switch fault | Often the small silicone tube on the inducer has slipped off. Reattach and reset. |
| C3 | Ignition failure | Igniter cracked or grounded out. Replace igniter assembly (~$50 part). |
| C4 | Flame sensor fault | Clean the flame rod with fine steel wool — oxidation is the most common cause. |
| C7, C8 | Gas valve fault | Replace gas control valve. Warranty-covered if within tier. |
| E1 | High limit reset | Manual reset on the limit switch. If trips again, scale on HX or thermostat issue. |
RTEX electric tankless error codes
The RTEX line uses a simpler 2-digit indicator:
- E1 — high-temperature shutoff (scale on element)
- E2 — element fault (test continuity, replace if open)
- E3 — thermistor fault (replace temperature sensor)
- E4 — flow sensor fault (clean inlet filter; replace if no resolution)
EcoNet app errors
EcoNet-equipped Performance Platinum tanks, ProTerra hybrids, and Prestige tankless push errors to the EcoNet mobile app rather than displaying on the unit. The app messages are typically plain-language (e.g. "Leak detected near unit", "WiFi connection lost", "Heat pump fault — switching to electric backup"). Open the app's Diagnostics page for full details and recommended actions.
When to call a pro vs DIY
DIY-friendly: code C2 (silicone tube reattach), code C4 (flame rod clean), code 14 (descaling), code P5 (filter clean), most "sensor failed" codes (sensor replacements are universally 20-minute jobs).
Service tech: codes 13, 71, 90 (combustion calibration), P3 (refrigerant-system diagnostic), any tank-shell-related code.
Bottom line
This page covers the codes that account for ~95% of Rheem service calls. For full troubleshooting context see our troubleshooting hub. For warranty claims after diagnosis see the warranty page. For parts shopping see the parts directory.