Vent: Stuck a thermal imaging camera on a 10 year old server and nearly had a heart attack

I was checking on an old Dell PowerEdge that's been running our file shares for years. Figured I'd use our new Flir camera just to see what's normal. One of the power supply units showed 195 degrees Fahrenheit on the back vent. Turns out the fan had been dead for who knows how long and the PSU was roasting itself. Lesson learned: don't assume older gear is fine just because it's still booting up. Anyone else find nasty surprises with thermal cams on aging hardware?

3 comments

3 Comments

ruby_jones28d ago

Yeah but 195 on a PSU vent isn't that crazy honestly, those things are built to run hot and they'll throttle themselves before they burst into flames. That little fan ain't what's keeping your data safe.

miller.emery28d ago

Throttling is exactly the point though. People see a high temp and panic, but those PSUs are specced to run at 90%+ efficiency in that heat range. The real risk is dust buildup caked onto the fan blades making them wobble. Then the bearing goes and suddenly your PSU is a space heater with no airflow. Seen that happen twice in older builds.

jade_jenkins28d ago

Boy, I completely disagree with both of you. I've been around hardware long enough to know that 195 degrees at the back vent means the internal components are likely pushing 220 or more. PSUs might be rated for high temps, but that rating assumes the fan is actually moving air across the hot spots, not just sitting there dead. The capacitors and MOSFETs inside that power supply degrade way faster when they cook like that day after day, and a sudden power surge or brownout is all it takes for a weak capacitor to fail short and take the whole board with it. I've personally seen a PSU with a dead fan smoke out a small server closet because the thermal protection circuits got overwhelmed by years of dust acting like an oven liner.