Burnham ES2 Series - C Wire Terminal

[Aceflyer]

Hi,
My old mercury thermostat (2 wired) recently died and replaced it with a Nest Thermostat 1st Generation (2020). I have a Burnham ES2 Series gas fired boiler (Model # ES24BNI-T).
After installing my Nest thermostat gave me an error N260 indicating that a C wire is needed. My thermostat is hooked up to R and W, and following it to the boiler, I see they are connected to terminals T, T on the IQ options panel. The terminals on that panel are 1,2,3,T,T.

Which of 1,2,3 would be the terminal I can use to tap a "C wire for my thermostat) (Or uses a Nest Power Connector either/ OR).

 

[Fitter30]

Looks like chassis ground should give you neutral. Page 34- 35
https://s3.amazonaws.com/s3.supplyhouse.com/product_files/Burnham-ES24BNI-T-Install-instructions.pdf

 

[Sponsor]

 

[Aceflyer]

Looks like chassis ground should give you neutral. Page 34- 35
https://s3.amazonaws.com/s3.supplyhouse.com/product_files/Burnham-ES24BNI-T-Install-instructions.pdf

Thank you @fitter30 . I am not really in electricals and circuits, but trying this out as a DIY project. So just to confirm what you mean is that I could hook up a "wire" to the chasis and run that into the thermostat as a "C Wire" - did I get that right? Thank you again for your response.

 

[Fitter30]

Yes hook to the chassis ground. Do you have a volt meter? If it doesn't work swap r and w and turning power off.

 

[Aceflyer]

Yes hook to the chassis ground. Do you have a volt meter? If it doesn't work swap r and w and turning power off.

Hi @fitter30 ,
Thank you - yes I do have a multimeter and reading up online, it appears that I need to measure 24v across the "T" terminal and the "chassis ground"/ common. Is that correct?
One additional question, if you don't mind. I was following along the "wiring diagram" for my model (https://www.ecomfort.com/manuals/burnham-7a8671872ebf1cea640cd96a9f3213f6.pdf). If you look at Page 35, it appears that the "terminal 3" of the EnviraCOM terminals (on the IQ options panel) [Lower Panel] is connected to "Ground". Do you think I can possibly hook up my "C wire" to this Terminal 3?

Thanks so much for your prompt responses. I really appreciate it.

 

[Fitter30]

Thats is the same as chassis ground if you follow the line up.

 

[Viki]

Hi Aceflyer. How are you.
I just see your conversation about Burham ES2 C (common wire) for Google nest thermostat.
How you solve your C wire problem with nest thermostat.
1 . You used Google nest power connector? If. yes is it work's? Or
2. For common wire which terminal you used. Terminal 1 , 2 or 3. I check voltage in all three terminals. Terminal 1 no voltage, terminal 2 9V Terminal 3 9V. I can not find 24V.
3. Or you put all the way new common wire from thermostat to Heating matchine.
PEASE explain me everything in detail. Or if possible please send some pictures.
Thank You.

 

[Fitter30]

Hi Aceflyer. How are you.
I just see your conversation about Burham ES2 C (common wire) for Google nest thermostat.
How you solve your C wire problem with nest thermostat.
1 . You used Google nest power connector? If. yes is it work's? Or
2. For common wire which terminal you used. Terminal 1 , 2 or 3. I check voltage in all three terminals. Terminal 1 no voltage, terminal 2 9V Terminal 3 9V. I can not find 24V.
3. Or you put all the way new common wire from thermostat to Heating matchine.
PEASE explain me everything in detail. Or if possible please send some pictures.
Thank You.

look at the right side of diagram you will see the chassis ground j box ground screw

 

[Dalangi]

Hi everyone. Just sharing that I was also installing a new Google nest themostat and I have a es2 burnham exactly like Aceflyer. I used the above suggestions and connected the common to 3, red wire to the T next to it, and white wire to the far right. Connected with no error codes. I got a weird com.Google.sso-260 code which I think at the end of many factory resets and reconfigurations, just needed my home address in my profile set. Either way Google nest is up and running! Thanks everyone. 7 years later using a battery operated Emerson when all I had to do is connect the c wire to screw 3. You live and learn.