C-505: Oxygen-deficient room alarm

Q: How do I check a C-505 fault?

1. Evacuate and do not enter 2. Ventilate per site procedure 3. Only trained personnel with gas monitors may investigate Safety: Nitrogen is an asphyxiant; check oxygen levels before entering enclosed spaces.

Probable causes

Nitrogen leak in enclosed room
Poor ventilation

Step-by-step checks

Evacuate and do not enter
Ventilate per site procedure
Only trained personnel with gas monitors may investigate

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 C-505 mean on a Nitrogen Generator?

C-505 usually indicates: Oxygen-deficient room alarm. Confirm the meaning in the manufacturer's manual for your model.

What causes C-505?

Nitrogen leak in enclosed room; Poor ventilation.

How do I check a C-505 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.