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High Rate of Fan Failures on 2821, 2851 & 3845

I am looking for suggestions to help me understand why I'm seeing a high rate of fan failures on my routers.

I manage 1500 routers, comprising 2821, 2851 & 3845. In the last 7 months, nearly 4% of these routers have exhibited a fan failure and I think that this failure rate is too high.

All of the routers are installed correctly in well-ventilated cabinets located in air-conditioned rooms.

I cannot determine if the fans are from a bad batch as they don’t appear in the device inventory. The router chassis themselves span several serial number prefixes, and the routers with fan failures span these prefixes also.

Although I’ve seen mention of IOS bugs for fan related syslog messages, there is nothing for my platform/IOS version.

The problem is most commonly resolved by replacing the fan assembly. I do not see repeat problems on the same device, and only once have I had to replace a chassis. This strongly suggests that the fan assembly is faulty rather than the chassis or bad connection.

Given that the fan itself is such a simple component, why am I seeing so many failures? I also manage many more switches than we have routers and I haven’t seen a single fan failure?

All suggestions welcome.


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Hall of Fame Super Gold

Re: High Rate of Fan Failures on 2821, 2851 & 3845

You should discuss this with you local Cisco sales office.

Cisco has an egnineering fault tracing program, also used to qualify or disqualify vendors, and they may want share the results with you.

Not that this will change the need to replace the router when a fault arise, but you will at least know what Cisco thinks about it.