Hi, I was going over the manual for Honeywell Vision Pro 8000 and noticed it can run on 24V system control power with battery as back up during power failure, if wire is run to connect C terminals between furnace control board and thermostat. I queried about this to Honeywell tech support to confirm it. If you did not know about this, check your manual, other non Vision Pro 8000 series thermostats may be same.
Nice they answered your question. My experience with VisionPro was that if you ask anything other than how to use it as a consumer, Honewywell tells you to get lost and they won't answer the question because you're not an authorized pro. In my case, I wanted to change one programmable setting on the "installer menu" and they insisted that I had to call one of those cigar smoking guys with his butt crack showing that charges $100. Fortunately all I couldn't remember was how to put it into installer mode so I could change the setting and I eventually figured it out.
BTW, one advantage to powering it is that the backlight is then on low all the time. With battery only, it only lights up when you touch it.
Heh? Maybe it has some thing to do with I being ex-Honeyweller? 3 AAA batteries don't last long in this particular 'stat.
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