I just installed a T6 into my home heating and cooling system. The problem is that I have no C wire but only can run the T6 on batteries. The problem with batteries is that the T6 when on battery power goes into sleep mode. Thanks to "aaiyar" for helping me diagnose the problem. In order to make my automations work correctly, I have to somehow wake the unit up or send the commands twice. This is not a reliable way of doing things.
My system consists of heating and cooling but I only have 4 wires coming to the T6. The wires are R-Y-W-G. My solution is to add one of these
to add the C wire 24V function to the T6 so it does not go to sleep. My question is, do you think this wall adapter will work. I really wanted this T6 to work properly and want to know what you think.
Are you certain there's not a 5th wire in the cable going to the stat (maybe tucked back into the wall hole)?
Assuming you're in the US, 18-5 cable tends to be more common than 18-4... Maybe you really do have 18-4, but I'd double-check that current cable by carefully teasing it out of the wall as much as you can to verify there's not a 5th wire tucked back.
When I needed to upgrade from 18/5 conductor to 18/7 conductor thermostat wiring, I verified that the old cable wasn't stabled to any stud, and then just used the old cable to fish the new cable from the air-handler to the thermostat. Didn't take more than 20 minutes. And didn't need to open any walls up.
Right on - good call. If it's truly 18-4 but possible to fish a new cable without too much butt-pain, that's absolutely the best answer... Go for 18-7 or 18-8 -- future-proofing for the win!
The braided cable is the one that goes to the T6 and the brown cable goes to A/C unit outside. It does look like there is an extra blue wire coming out of the braided cable so it is a 5 wire like you said. White red green blue and orange. Also note that there is nothing attached to the Y terminal but there is a Y wire orange at the T6. The orange wire is connected to the red wire on the brown cable. I am getting more confused as I research this. I may be in over my head.
Well the white wire in the brown casing (not braided) is your c-wire. Match that up in the thermostat. W is for Heating, Y Is for single stage AC compressor. Who the hell wired up this mess? Check your AC compressor wiring. (Do you have AC?)
Well, that's a c-wire, but it's for the external A/C condenser. That's OK to leave as is. More ideally, he'd take the unused blue wire from the braided bundle and put that under the C terminal at the furnace -- no issues at all with putting both C wires under that terminal -- it's designed for that. Then he'd have C at the stat too.
Unfortunately, it looks like original installer may have chopped the blue wire in the braided bundle really short -- it would suck if they did the same thing on the stat end. No problem splicing that to get more length, but that may be tough on the stat end.
I have no idea why the orange Y is going straight to the condenser's red Y -- I've only ever seen those both of those Ys connect under the furnace board's Y terminal, but I'm not an HVAC expert.
Right now on the T6, the white goes to W, orange goes to Y, green goes to G, red goes to R which has a slider that connects it to RC. It looks like the orange wire is getting it's inputs from the brown cable red wire coming from the A/C unit outside.
The adapter supplies common and is hooked to the C terminal and RC terminals and the slider will have to be moved down to allow the connection to the RC terminal. $20 bucks for an adapter providing it will work and not screw things up is a pretty good option at this point.
I just removed the T6 from the wall, and there is no way I can get to the blue wire. I have no extra wire coming from the wall. The only thing I can think of is running a new wire just for the C function.
I suppose we should try to clear up some assumptions here -- My guess is we're dealing with a single-stage furnace and single-stage air-conditioner... The air conditioner's condenser is the extrenal unit, and all "air-handling" (heat or cool) is done through the furnace/air-handler's control board.
In that case, just two wires come from the external A/C condenser - Y and C. In my (limited!) experience, both of those connect to the respective terminals at the furnace control board.
The wires from the stat each attach to their corresponding terminals at the furnace control board.
That means you commonly have two wires at the C and Y terminals on the furnace board.
I haven't ever seen connecting the stat's Y directly to the condenser's Y, but apparently that's been working fine for OP, so rock on... I've just always thought there must be some good reason they're usually connected at the furnace control board, but perhaps that's not always necessary.
You are correct, single stage furnace and a/c unit outside. I don't know why the Y is ran outside to the a/c unit and not connected to the Y terminal at the circuit board.
I am going to try to run a C wire only from the circuit board to the T6 and see what happens. I will let you all know when I get this done and if it works. I didn't want to go to all this trouble but that's life.
