r/Nest 3d ago

Did I mess something up?

I set up our Nest Gen 3 yesterday and the AC worked fine for hours no issues. Today the system now loses power, makes clicking noises before it turns on again and repeats. I was messing around with settings and put it in heat and cool mode before going to bed last night which didn't work as intended. Then we had to turn off eco mode today cuz it wasn't turning on manually either.

Looking back at my work it looks like I put the Heat wire in the wrong place but it didn't give me issues yesterday. I wasn't sure about it due to the labeling in the old thermostat. After doing some research, it seems like the Nest just isn't getting enough power anymore. I noticed we also have a blue wire that wasn't used with the old thermostat that is still tucked in the wall and it seems to be a C-Wire. I looked at the furnace circuit board and I do see a blue and white wire connected to C.

I wanted to see if anyone might know what the problem might be before I try anything and plug in wires that weren't being used with the old thermostat.

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u/ebusch73 3d ago edited 2d ago

Since you have a spare blue wire in the wall, which already seems to be connected at the furnace end, plug that into the Nest's C terminal. That should help to keep the Nest fully charged.

The white wire into W1 for heating is correct. Your old thermostat has alternate labels for a heat pump (the O and B terminals) and in that case the white wire would have gone into W2/Aux. You appear to have a conventional A/C so W1 is the correct terminal for your system.

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u/[deleted] 2d ago

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u/ebusch73 2d ago

I'm well aware that they don't have a heat pump. If they did, either the O or B terminals would be used, but they weren't.

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u/[deleted] 2d ago

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u/ebusch73 2d ago edited 2d ago

Again I'm fully aware. The OP mentioned they thought they messed up their white heating wire. Presumably they saw the original "W/Aux" label and put it into the "W2/Aux" terminal on the Nest. That would have been correct had they had a heat pump with aux electric heat, but with a conventual A/C and electric furnace it should go into W1.

In this case the "Alternate Label" is W for conventional and Aux for Heat Pump.