Quantifying racked gear temps

[Jonathan Starr]

I had a power supply transformer go out on a piece of racked tube gear recently, and it got me thinking about trying to measure and control temperature of my outboard gear in the racks.

Unfortunately, I can't afford the luxury of full spaces around most stuff. I wish that the holes in rack rails were evenly spaced, so I could add a partial rack space between stuff. I don't understand the logic of the uneven hole spacing standard.

I am hoping to avoid adding fans to the racks, due to noise. I try to arrange gear partially with an eye to allowing hotstuff to hang out with shorter boxes above.

Anyway, I have a digital temperature accessory and flexible probe for my trusty old Fluke multimeter (motto - if it works it's a fluke) and I've started measuring the temp by sticking the probe into the narrow space between gear, from the rear. The probe is pretty thin and would fit into a screw hole or vent slot to measure temps inside the gear, but I am nervous about causing a more acute and immediate problem by attempting to do so.

I am typically seeing temps around 115 to 120 farenheit between units that are warm to the touch.

My newer outboard racks are Quiklok steel units with mesh sides and top, which seems to help the ceiling fan and a/c do their jobs (except when I'm tracking in the control room, which is rare).

My Omnirax desk has 2 4-space cubbyholes below my monitors, which are the most convenient location for fingertip accessible gear, but they are surrounded by solid wood top, bottom and sides and are the worst culprits for heat.

Does anyone have a better way to do this, or some empirical temp ranges that spell danger?