W-504: Oxygen analyser fault

Q: How do I check a W-504 fault?

1. Check analyser status 2. Calibrate with reference gas 3. Replace sensor per OEM interval Safety: Nitrogen is an asphyxiant; check oxygen levels before entering enclosed spaces.

Probable causes

Sensor end of life
Calibration due

Step-by-step checks

Check analyser status
Calibrate with reference gas
Replace sensor per OEM interval

Safety: Nitrogen is an asphyxiant; check oxygen levels before entering enclosed spaces.

Sample code — verify with the OEM manual for your exact model.

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Frequently asked questions

What does W-504 mean on a Nitrogen Generator?

W-504 usually indicates: Oxygen analyser fault. Confirm the meaning in the manufacturer's manual for your model.

What causes W-504?

Sensor end of life; Calibration due.

How do I check a W-504 fault?

Work through the numbered checks above in order, recording readings as you go. Nitrogen is an asphyxiant; check oxygen levels before entering enclosed spaces.

Other Nitrogen Generator codes

Disclaimer: Fault code information is guidance only. Codes and meanings vary between manufacturers and models — always follow the manufacturer's manual and your site's safety procedures, and use qualified personnel for electrical, pressure, refrigerant and combustion work.