e003
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Navien · Tankless Water Heaters
Ignition failure: unit could not establish burner ignition.
Quick Answer
Error code E003 on your Navien Tankless Water Heaters means: Ignition failure: unit could not establish burner ignition.. This is usually fixable — see the step-by-step guide below.
Affected Models
Likely Causes
How to Fix It
1
Confirm gas supply valve is open.
2
Power cycle the unit and retry once.
3
Inspect vent/air path for obstruction.
4
If repeated, have technician test ignition and gas pressure.
5
Service burner/ignition components as required.
Pro Tip
This issue typically requires professional diagnosis. Attempting this fix without proper training could cause further problems.
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