E74 error when installing thermostat

[Ehawthorn]

Hi there!

I have spent the day trying to resolve an issue with installing my nest thermostat. I have a burnham ES2 boiler and a three wire set up (W, Rh and C). 

Since trying the initial setup I have continually received an e74 error despite trying all trouble shooting measures. I have charged the battery using a USB wall charger and the battery drains VERY quickly. I have had to charge it twice for 2+ hours today in between trouble shooting  ideas.

I have checked all wires, and the furnace, ensured everything was on. And the old thermostat works perfectly fine. My boiler does not have an outdoor drain pipe - it is under the floor - so it can’t be inspected for a clog. 

any other ideas?

[CranberryJammer]

Did you solve this? I have a similar issue!

[Jake]

Hey all,

Apologies for the late reply. I wanted to follow up and ensure you are good to go. Please let me know if you are still having any trouble from here, as I would be happy to take a closer look and assist you further. 

Best regards,
Jake

[Ehawthorn]

Hi Jake,

After consulting two HVAC techs they determined my house is not compatible with any smart thermostat. It’s too bad.

thanks 

[Jake]

Hey Ehawthorn,

Glad to hear you were able to get help on the issue. I am sorry to hear your system is not compatible at this time, that is a little unfortunate. With the issue being resolved, I am going to lock the thread at this time. If you run into any questions from here, please feel free to create a new post. Have a good one!

Best regards,

Jake