Navien Error Code E003

What Does E003 Mean?

Error code E003 indicates an ignition failure - your Navien boiler is unable to light the burner.

Common Causes

1. Gas supply issue - gas valve closed or low pressure
2. Faulty ignition electrode - unable to create spark
3. Blocked burner preventing proper gas flow
4. Air in the gas line after recent work
5. Faulty gas valve not opening properly
6. Flame sensor contamination preventing detection

What You Can Do

Safety First

⚠️ Never attempt gas work yourself - always use a Gas Safe registered engineer.

Safe Checks

1. Check other gas appliances in your home - do they work?
2. Verify the gas supply is turned on at the meter
3. Listen for clicking when the boiler tries to ignite
4. Check the display for any other error codes

Reset Procedure

1. Turn off the boiler using the control panel
2. Wait 2-3 minutes
3. Turn the boiler back on
4. If E003 returns, do not keep resetting - call an engineer

When to Call an Engineer

You should contact a Gas Safe registered engineer for:

• Persistent ignition failures
• No spark sound when boiler attempts to ignite
• Gas supply issues after checking other appliances work
• If you smell gas (turn off supply and call National Gas Emergency: 0800 111 999)

What the Engineer Will Check

• Gas pressure at the boiler
• Ignition electrode condition and gap
• Burner cleanliness
• Gas valve operation
• Flame sensing circuit
• Electrical connections

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Applicable Models: NCB-CE, NCB300, NCB500, NCB700, LCB700, and NPE series.