Thermostat -- app says I have extra wire (I don't)

Simple two-wire oil burner worked for two years with a dedicated 24V doorbell transformer powering the thermostat.

Thermostat worked reliably, as well as the app’s shortcomings allowed. This fall I occasionally used the app to check the temperature in the living room where the thermostat is installed. All was still well until a couple of weeks ago when the app said the thermostat was not connected.

I tried getting the app to reconnect but nothing worked, so I removed the thermostat from the app and tried to reinstall. Nothing, so I removed it again, factory reset the thermostat, and started anew.

It connected to Wi-Fi, but then I got an error message saying I had an extra wire connected (photo 1).

I pulled the thermostat and checked. I even cleaned the connector of this phantom wire and securely reconnected the adjacent common wire (photo 2).

I tried another factory reset to no avail.

Ideas, anyone?

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It is telling you you have 5 extra wires. Every single open lug.

Are all the pins on the back of the head still in good shape?

With it telling you that there are 5 extra wires on every empty lug, I would suspect there is a short somewhere or that the thermostat got power spiked and is baked.

Have you tested the voltage with a meter?

Keep pressing try again until it lets you skip/ignore.

3 Likes

Thanks, SlabSlayer. Actually the app showed all but one empty connector with an extra wire. I was fooled by the red “frame” around the bottom one and overlooked the top ones you caught, but we both missed W2.

The device had power as evidenced by coming on and giving me fits. The pins are straight and like new. And now, the darn thing is working as it should. I’ll comment the solution in my reply to speedie below.

Thanks for your comment and suggestions.

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Thanks, speadie. I started again and this time took no prisoners. I kept at it and the app finally allowed me to “skip” (it said, but not really) the step.

Next, it asked me what kind of system and wiring I have. After telling it oil and forced air, it asked if I had certain wires (I don’t recall which, but it asked about two wires, I think). After I answered these questions, the app congratulated me on a successful setup. Now it works fine, as it should.

Thanks for your suggestion. Persistence paid off.

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Remove the Rh wire and it will work. I had the same problem.