Voltage regulator for thermostat?
I have three identical HVAC systems in the house. Recently I switched to those Nest thermostats which have a lot of nice features for gadget/control freaks. We've been very happy with them.
However, one system in the house blew an internal fuse (on the green fan power line) inside one of the Nests after just a few weeks. They sent a replacement overnight, and within a couple weeks more, it blew a different internal fuse (this time to the yellow heat/cool line). The Nest logs a ton of data and tech support requested permission to download that. They saw some voltage spikes and recommended that I install an inline voltage regulator.
They are sending a replacement and I have agreed to not install it until the overvoltage problem is corrected. I know I can pick up a little 3-leg TC-package 24V 1 amp regulator for about $2, but I'm not sure where to install it (or them).
One for each control line going into the thermostat? (My systems are all heat pumps using yellow, green, orange, aux-white, and red Rc... and blue common, of course.) Or just some of the lines? Or somewhere else in the system?