I may have missed it earlier in the thread, but is the cover to your HVAC still removed by chance? They will commonly have a tamper switch that kills functionality.
The cover is back on. No good.
Did you start removing wires/old thermostat before powering down? Blowing a fuse is pretty common in that scenario.
But yes, I would recommend having a technician take a look if you can verify your HVAC is powered on, no tamper switches are open, and you are receiving no voltage at thermostat.
If the wiring is fairly old, it could likely be as simple as a broken wire. Solid cable is very susceptible to damage from a lot of bending/movement. Have you by chance tested the resistance on the wire as described in previous posts?
I threw the circuit breaker before messing with anything.
I haven’t done any resistance testing, but I’m to the point where I’m over it, so I’m throwing in the towel. I’ve got a tech scheduled to arrive today.
Appreciate everyone’s help; I’ll let you know the verdict.
Blown fuse somewhere inside the bowels of the air handler. No clue how I did that, but it is what it is.
I still have the thermostat that the HVAC company included with the install of the system, so I’m going to have him put that back in. If I use that tstat, and he installs it, the parts warranty on the system will be restored.
Service call, diagnostics, fuse replacement, and install of customer-supplied tstat: $260. Could have been worse I guess.
Could have been worse, but you could have saved yourself $260 had you followed suggestions… a fuse runs a couple bucks or so.
You should always keep the paperwork for your unit, it has a schematic, and tells you where everything is.
Either wire is broke, disconnected at unit, or unit may be damaged. This assumes that unit has power as you stated previously, and it is just not getting to the tstat. Verify again all fuses, breakers, disconnects. Flip them on/off, remove and reinsert all disconnects (probably two inside, and one outside)
You can put your tstat back on after the tech leaves. Just keep it so you can put it back in event you need HVAC warranty work in future. Most (Carrier/Bryant at least) only warranty 5 years if you fail to register unit soon after installation (otherwise if you do register it within 90 days of installation, it is 10 years). Problem is, the new homeowner isn’t told, and by the time you realize it, its too late.
You probably did not throw the proper breaker for the air handling unit. Most likely you have two breakers relating to your HVAC; one for the condensing unit outside your house that is probably a dual-breaker setup, and one for the interior unit that is a single 15A or 20A breaker. I wish I would have seen this for you sooner, as I have made the same mistake.