E-501: Low nitrogen purity

Q: How do I check a E-501 fault?

1. Check feed air dew point and filters 2. Reduce flow to rated value 3. Arrange purity analyser check Safety: Nitrogen is an asphyxiant; check oxygen levels before entering enclosed spaces.

Probable causes

Feed air too wet or oily
Carbon molecular sieve degraded
Flow above rating

Step-by-step checks

Check feed air dew point and filters
Reduce flow to rated value
Arrange purity analyser check

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 E-501 mean on a Nitrogen Generator?

E-501 usually indicates: Low nitrogen purity. Confirm the meaning in the manufacturer's manual for your model.

What causes E-501?

Feed air too wet or oily; Carbon molecular sieve degraded; Flow above rating.

How do I check a E-501 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.