Navien NCB300-28K, Service Manual

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44 System Details
4.7.8 Burner
Item Description
Function
1. Pre-mixes air and gas to reduce emissions and increase efficiency.
2. The burner produces the optimum air/gas mixture required to produce the correct level of heat during
combustion.
Fault
1. Unable to initiate or sustain combustion.
2. Dust or soot deposits form on the burner’s surface.
3. Gas leakage from the burner.
Symptoms
1. Abnormal combustion.
2. Unstable flame conditions and / or flame loss.
3. Ignition failure.
Error codes E003, E004, E012
Diagnostics
Visual inspection: Check for deposits forming on the burner surface and / or unstable flame conditions
during operation.
Fuel gas supply
Combustion air supply
Burner Body
(Gas/air mixture and combustion zone)