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Noritz · Tankless water heater troubleshooting

Cleaning the fan and burner - Noritz EZ/NRCR/CDV

What is going on

Premix units: a dirty fan or venturi lowers air and gas to the burner (code 90 on older installs).

Likely causes

  • Dust and lint drawn in with combustion air

Check in this order

  1. Warning: Shut off the gas and power first.
  2. Remove the mounting bracket (2 screws).
  3. Remove the c-clip and carefully pull the gas valve off the venturi; do not damage the o-ring.
  4. Unplug the fan harness and remove the 4 screws holding the fan to the burner.
  5. Take out the fan and venturi, then separate the venturi from the fan.
  6. Clean the fan using a plastic brush, vacuum or compressed air. Never take the fan housing apart; if it won't come clean, replace the fan.
  7. Clean the burner with a vacuum only. Never use an air compressor on the burner; it can damage the burner mesh.
  8. Reassemble with the gas connection lined up with the triangle on the fan housing, keeping all o-rings and gaskets in place; leak test the gas connection.

Applies to: Noritz premix: EZ, NRCR, NCC199CDV

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Source: Noritz EZ/NRCR/CDV Level 2 Maintenance & Troubleshooting (Premix R2 V2), Cleaning fan & burner, p.7-10. Written in our own words; check the manual for your exact model.

For licensed technicians. Gas, electrical and refrigerant work must be done by a qualified, licensed person. Shut off power and gas before servicing, never bypass a safety control, and follow the manufacturer’s manual for the exact model; it and local codes always take priority. HVACopedia is not affiliated with any manufacturer; brand and model names only identify the equipment.