SMT1500 fan runs constantly at varying speeds even when UPS turned off

[Anonymous user]

I do not have this problem with my SMX's, the fan runs all the time but at a constant speed. Normally when I hear a fan running at  constantly varying speeds I suspect the fan bearings need to be lubricated or the fan needs to be replaced.

[BillP · Accepted solution]

I don't disagree with you but we have some detail here regarding Smart-UPS fan operation -> http://www.apc.com/support/index?page=content&country=ITB〈=en&locale=en_US&id=FA156553 

"SMT" and "SMX" models use a variable speed fan. The speed is determined by multiple factors such as operating temperature, mode of operation, and load.

This operation may vary depending on the model and firmware revision of the UPS. Ensure your UPS has the most recent firmware revision installed for optimal fan operation.

I haven't heard of any fan issues in any firmware version really but we could verify what firmware is on the unit to see if it is worth a try to see if it changes after a firmware upgrade.