Navien Tankless Igniter/Flame Rod Replacement — What This Part Does
The igniter and flame rod assembly in a Navien tankless water heater does two jobs. The igniter electrode creates a spark to light the gas burner when the unit calls for hot water. The flame rod then senses the presence of the flame and sends a signal back to the control board to confirm successful ignition. Both components are usually mounted together as one replaceable part.
This assembly fails when the surfaces get coated with carbon deposits, dust, or condensate residue that prevents proper spark generation or flame sensing. Physical damage like cracks in the ceramic insulator, corrosion on the metal rod, or age-related wear also cause ignition failure. Dirty or failed igniter and flame rod assemblies are the most common verified cause of ignition lockouts on Navien tankless units.
Signs It Needs Replacing
- Error code 003 on the display The unit shows a code 003 ignition failure and will not fire the burner.
- Clicking or sparking sound with no ignition You hear the igniter clicking repeatedly but the burner never lights.
- Delayed ignition or intermittent firing The burner takes several tries to light or ignites and then shuts off immediately.
- No hot water and burner stays off The unit runs its fan but the burner does not light when you open a hot water tap.
- Visible carbon buildup or white deposits on the flame rod Opening the cover reveals black carbon or white condensate residue coating the igniter or flame rod.
- Cracked ceramic insulator on the igniter electrode The ceramic body around the igniter tip is chipped, cracked, or broken.
How to Replace It
- Turn off electrical power to the water heater at the breaker or disconnect switch.
- Turn off the main gas supply valve to the unit.
- Remove the front cover panel by loosening the screws at the bottom and lifting the panel off the clips.
- Locate the igniter and flame rod assembly mounted inside the burner chamber and disconnect the sensor wire from the flame rod terminal.
- Unscrew or unclip the igniter and flame rod assembly from its mounting bracket and carefully pull it out of the burner area.
- Install the new igniter and flame rod assembly in the same position and secure it to the mounting bracket.
- Reconnect the sensor wire to the flame rod terminal and verify all connections are snug and properly seated.
- Replace the front cover panel and restore gas supply by opening the main gas valve.
- Restore electrical power and clear the fault code by pressing the reset button or cycling power, then open a hot water tap to test ignition.
The Part You Need
| Part | Notes |
|---|---|
| Navien igniter and flame rod assembly | Amazon | Navien part number 3002665A fits most NPE and NCB models. Find your exact model and serial number on the data plate inside the front cover or on the right side of the unit to confirm compatibility before ordering. |
When to Call a Pro
Gas appliance ignition work requires verifying gas pressure, proper combustion, and safe venting after reassembly. If you are not experienced with gas-fired equipment or do not have a way to test gas pressure and confirm proper burner operation, call a licensed technician to diagnose and replace the igniter assembly. Also call a pro if the new igniter does not fix the problem, since ignition failures can be caused by upstream gas supply issues, blocked venting, faulty gas valves, or control board problems that require diagnostic tools and training to resolve safely. For gas line, burner, or igniter work, or if you ever smell gas, stop and call a licensed technician.