Quote Originally Posted by anendeloflorien View Post
It may just be a grounding issue or it could be that it's just the sounds of the flexwatt warming up, the plastic expanding and contracting a little bit. Is it just when it's first turned on or is it a constant buzzing? I've never noticed that on the flexwatt on any of my racks and I wired up a lot of it myself.
Mine buzzed when resistance was applied via a proportional thermostat at less than 100% power. If it was cranked up or on and on/off thermo - it didn't buzz.

Switching to a grounded stat stopped the problem (the flex was already grounded).