Case 3: The Phantom of the Heated Stage

Lab C: Something is odd with the heated stage. I've been doing some tests and I don't think it is the loggers... but I’m stumped!

We log the temperature of our heated stage 24/7 with the BrightSentinel loggers. Lately, I've been noticing that the temperature readings for the left-back side of the heated stage drops by a few degrees more than the other 3 loggers every morning; the trough is around 5.00 am. By 7.30 am the readings are back within temperature range and are consistent throughout the day.

What makes it doubly odd is that the Day/Night Report indicates that the temperature recorded by all 4 loggers on the heated stage increases slightly overnight but this particular logger goes crazy and drops every morning like clockwork! What do you think is happening?

BrightSentinel: Do you have an air-vent above the left side of that heated stage?

Lab C: Yes, we do. Surely it can’t be the air vent? It has been there all along.

BrightSentinel: OK. Let’s try an experiment. Would you mind sticking a sheet of paper over the air vent so that we can eliminate the air vent?

Lab C: Ha ha! I’ll probably get in trouble with OH&S for doing this but let’s give it a try. I’ll be in touch in a couple of days.

BrightSentinel: OK. Good luck and be careful.

Four days later …

Lab C: Interesting! By using the sheet of paper, the logger on the left side of that heated stage did not cool down as much but it was still noticeable.

It turns out that Building Maintenance recently implemented some energy saving measures. When the building is empty in the evenings, the temperature is allowed to rise a couple of degrees. Every morning, before the building fills up with people, the system kicks in to bring the environmental temperature back to the acceptable level. The building maintenance manager was surprised to hear this and see the graphs. The temperature level and flow into the lab is being fixed. Thanks!