Error M20/E298

[Chergirl9]

Thermostat keeps saying "no power" and giving error codes M20 & E298 no matter what I do. 

I correctly installed the c-wire power connector. There are no shorted fuses on my control board. My furnace is powering just fine.

When I look at the equipment errors, it says it cannot detect the W, R, and G wires (aka all the wires I connected). I tripled checked that they are in there securely, I trimmed the ends of the wires so there's fresh copper, and the Thermostat is seated properly.

I am at an utter loss. Please help.

[Patrick_Caezza]

Post a picture of the original thermostat's wiring here.

Is this a heat-only system? Is it a boiler, furnace, or something else?

With only the W, R, and G wire, the Google Nest Thermostat needs the C wire installed. Depending on the type of heating system that you have, you might need to also install an external 24VAC transformer with the Nest Power Connector.

[MeltingInDallas]

…you might need to also install an external 24VAC transformer with the Nest Power Connector. I think this may be what I need. Where can I find more info?

[MelbaDT]

Hey MeltingInDallas, 

Thanks for chiming in. You may check on this link for more information about our Nest Power Connector: https://bit.ly/3z34z2e

Best, 

Melba

[MelbaDT]

Hey there, 

Checking back in should you have further questions here. Feel free to reply to this thread. 

Best, 

Melba

[MelbaDT]

Hi, 

We haven't heard from you in a while so we'll be locking this thread if there is no update within the day. If you have any new issues, updates or just a discussion topic, feel free to start a new thread in the Community.

Best, 

Melba

[Chergirl9]

This is my original wiring. It is a heat-only system.

I did connect the c-wire power connector to my furnace's control board. 

[Patrick_Caezza]

Your wiring looks just fine.

What is your heat source? Boiler, furnace?

How did you wire the Power Connector to the heat source?

[MelbaDT]

Hey folks, 

Appreciate your help, Patrick_Caezza. 

Chergirl9, I'm jumping in to ensure everything is good here. Have you've seen Patrick's last response? Let us know of the answers so we could take a closer look at them. 

Best, 

Melba

[MelbaDT · Accepted solution]

Hey Chergirl9, 

How's it going with your thermostat? Still need our help?

Best, 

Melba

[Chergirl9]

Thank you for the follow-up. It turns out the issue was a loose wire at the furnace. It works great now!

[MelbaDT]

Hey there, 

You're welcome and I'm glad to hear that you've sorted it out  and now, you have a thermostat that is working as it should. 

Cheers, 

Melba

[MelbaDT]

Hi, 

We haven't heard from you in a while so we'll be locking this thread if there is no update within the day. If you have any new issues, updates or just a discussion topic, feel free to start a new thread in the Community.

Best, 

Melba