Herpstat Probe - Buzzing Noise?

One of the two temperature probes on my Herpstat II is making a low buzzing noise. It's not particularly loud, but loud enough to be rather noticeable in a quite room. Anyone else have a similar issue? Is it something I should be concerned about? The Herpstat is only a few weeks old and this is the first time I've noticed it.

Perhaps I was mistaken and it is the flexwatt itself buzzing and not the probe, though for some reason it seems to be loudest near the probe location.

Re do the connections, and also check the fans in the herpstat.

Yup I have had the flex watt buzzing in my case it was a broken partial connection re do the points where you hear it and keep doing it until the sound goes away. If you are like me I couldn't do one at a time and ended up ordering new flex watt and doing the whole thing again and then trading the new for the old. I couldn't pull out one length at a time to work on it and pulling the whole thing left snakes with out heat for a very long time so I had no options really but rebuild the whole works. :mad: Oh well in the end it was much better I didn't wire the fist time around it came with the rack I bought used it is much more energy efficient now. (better wire and perfect connections saves line loss)

I had the flexwatt sitting on some aluminum foil to reflect a bit of heat upward and improve efficiency. I took it out today and, low and behold, the buzz went away. It only buzzed when the herpstat was at less than full power, some opinions I've read elsewhere about this seem to indicate that the buzz is not from any kind of electrical short but rather some kind of harmonics caused by the proportional thermostat that causes resonance within the flexwatt. Either way, the buzz is gone now, so I guess I'll just forego the aluminum foil and perhaps try another piece with solder when I get around to it and see if it does the same thing on the foil.