thermostat
I'm trying to install a smart thermostat. I have a Honeywell programmable thermostat now. However, I found that there's a wall plate in back of the back plate, and it's secured to the wall (not by screws) and I don't know how to remove it.
I tried to search on Google and YouTube, but I didn't find anyone who has the same problem. I'm guessing this is a non-typical setup?
Any idea about how to remove this wall plate?
I think you're out of luck, since the G wire passes through the ventilation control system. You have to leave the G wire as a G wire, or remove/bypass the ventilation system. The easiest solution, would be to run a new 5 wire cable. Or don't use a fancy thermostat.
If you follow the G wire through the system, you can get a better picture of what's going on.
When the thermostat energizes the G terminal, the Gt terminal on the ventilation control receives the signal. The ventilation control does whatever it does, and eventually energizes the Gf terminal. When the Gf terminal is energized on the ventilation control, the furnace receives the signal and starts the blower.
From what I can tell based on the images, this is what the whole system looks like.
On a side note. The installer that left that rats nest of wiring in the furnace, should be ashamed of himself.
It's likely not connected to anything. If you go to the furnace, you'll likely see the cable that goes to the thermostat. You'll also likely see the brown wire either wrapped around the cable, or just not connected to anything.
Best Answer
The back plate was meant to be held on by screws into the plastic anchors visible on one of the photos.
If the screws are out and the plate is still attached to the wall, it is likely that paint or compound are holding it on.
Try scoring around the edges with a utility knife, then slipping a putty/taping knife behind the plate and prying it off. There may be some minor cosmetic damage to the drywall or paint.