Honeywell YTH8320ZW1007 Dead on Arrival??

I just purchased the unit from Amazon and I can not get the screen to show anything. When you pull the battery tab the screen should turn on correct? The screen hasn’t lit up at all. Any help would be greatly appreciated!

My recollection is that the display only runs when the unit is connected to main power–the battery is just for clock backup during power outages. On one of the two I bought, the onboard battery spring-clip wasn’t quite snug enough against the battery for solid contact, and I would have it lose track of time when I removed it from the wall.

But no, I don’t think your unit is DOA. I think you’re going to have to wire it up to see the display do anything.


Thanks for the reply Richard I did wire it up exactly the same way my previous thermostat is wired and even when I snapped it in I still had no power. Do you know what that thp9045 wiring module is for?

I just read on Amazon that someone else had a DOA stat like yours. I buy 100’s of Honeywell stats per year, though not all 8000 models. DOA’s are very rare, but I do have a few.

If these stats are anything like the normal 8000 the display should power on with just the batteries, they tout that as a feature in that you can program it from the comfort of your lazy boy and then go put it on the wall adapter.

Take the batteries out and make sure you didn’t get some of the separation paper torn off between the battery and contact. Maybe even take a pencil eraser to the battery ends and contact ends. Also make sure you have 24v at the thermostat, quite often people blow their low voltage fuse when they change thermostats. If that doesn’t work, Amazon is excellent with returns.

I think I may have blown the fuse or tripped the breaker. I tried to install it in my master bedroom just to make sure and it worked in there. It did need the power from the wall. Now my old thermostat downstairs (where I tried to install the new thermostat first) isn’t working and I can’t get the ac/heat to power on at all. I’m going to check tomorrow when it’s daylight if I tripped the breaker. I sure hope that’s all it is. Lol. Thanks again for the help everyone. This is only my second day with my Vera 3 and I’m loving it.

I just installed that t-stat and it did come with a dead battery. I believe the coin battery was 3.2 volts and only measured 1.2.

That really is not what powers the screen though. Most t-stats use 4 wires where the honeywell you have requires 5 wires with an adtnl “common” wire needed to power the screen. The thp9045 enables you to still use your 4 wire set up and split one wire to enable use with the new t-stat. I went ahead and just ran another wire so I had 5 with mine and it works just fine.