Navien Error Code E110: Exhaust Blocked
Warning: Your Navien boiler or water heater has locked out due to an exhaust blockage; do not keep resetting—this indicates a potential safety issue that needs professional inspection.
How to Fix Navien Code E110
- Step 1: Check the outside exhaust vent terminalu2014clear away any snow, ice, leaves, or debris. Do not remove the vent pipe.
- Step 2: Press the reset button on the unit once (if equipped). If the code returns immediately, do not keep resetting.
- Step 3: If the outside vent is clear and the code returns, call a qualified Navien technicianu2014do not attempt to disassemble the exhaust system yourself.
How to Reset Navien Code E110
- 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.
What does E110 mean?
The E110 code on a Navien unit means the control board detected that exhaust gases are not flowing properly out of the flue pipe. This can be because the exhaust pipe is blocked by debris, snow, or ice, or because the combustion fan cannot push the gases out due to a restriction. The unit shuts down to prevent carbon monoxide from backing into the home. This code is common on condensing models where the plastic exhaust vent can become clogged with ice in winter or with debris over time. Do not attempt to operate the unit until the blockage is cleared, and always have the vent system inspected annually.
Affected Models
- NCB-H
- NFB-H
- NFC-H
- NHB-H
- NHW-A
- NPE-A2
- NCB
- NCB
- NCB
- NPE
- NPE
- NPE
- NHB
- NHB
- NCB
- NCB
- NPE
- NPE
- NCB
- NCB
- NPE
- NCB
- NPE
- NHB
- NCB
- NPE
- NPE
- NCB
- NCB
- NPE
- NPE
- NPE
- NPE
- NHB
- NHB
- NCB
- NCB
- NPE
- NPE
- NBP
- NPE
- NPE
- NPE
- NFC
- NFC
- NCB
- NPE
- NPE
- NPE
- NCB
- NPE
- NCB
- NPE
- NPE
- NCB
- NPE
- NHB
- NPE-S
- NPN
- NPN
- NCB
- NPE
- NCB
- NPE
- NHB
- NPB
- NFC
- NFC
- NHB
- NPF
- NPF
- NPE
- NHB
Source Documentation
| Manual | Page | Reason | Action |
|---|---|---|---|
| NFB-H Installation & Operation Manual | 116 | Exhaust Blockage | Check exhaust venting. |
| Navien NCB-H Installation & Operation Manual | 129 | Exhaust Blockage | ● Ensure that the exhaust pipe is free of obstructions. ● Clean the intake air filter. |
| Navien NFB-H Installation & Operation Manual | 116 | Exhaust Blockage | Check exhaust venting. |
| Navien NFC-H Installation & Operation Manual | 127 | Abnormal air pressure | Manual RESET |
| Navien NHB-H Installation & Operation Manual | 119 | Exhaust Blockage | Check exhaust venting. |
Recall Notices
Navien Tankless Water Heaters and Combination Boilers Recalled Due to Carbon Monoxide Hazard
19-027
LP gas conversion kits can cause units to produce excessive carbon monoxide.
Replacement Parts
| Part | OEM Number | Est. Cost |
|---|---|---|
| Combustion Fan Assembly | 30023130A | — |
| Exhaust Vent Termination Kit | — | — |
| Condensate Trap Assembly | 30026873A | — |
Related Codes on Same Models
| Code | Description | Severity |
|---|---|---|
| E001 | Ignition Failure | Warning |
| E003 | Abnormal Ignition | Warning |
| E004 | False Flame Detection | Warning |
| E012 | Flame Loss | Warning |
| E016 | Overheating | Warning |
| E030 | Exhaust Overheat Sensor | Warning |
| E031 | Inlet Thermistor Open/Short | Warning |
| E046 | Outlet Thermistor Open/Short | Warning |
| E047 | DHW Thermistor Open/Short | Warning |
| E060 | Fan Motor Abnormality | Warning |