Boiler constantly on after Nest installation

[ab22]

Installed a Nest Thermostat 3 on Baxi 830 boiler; wired in Opentherm. 

Heating and hot water work, all controls work, however the boiler is constantly on, even when heat is zeroed or turned off.

Any ideas? Thanks in advance.

[EdwardT]

Hi ab22,

Thanks for reaching out. I'm sorry to hear that you're having an issue with your Nest Thermostat. I'd love to know more about this and I have a few questions:

• What type of Nest Thermostat do you have?
• Where are you located?
• How is your Nest Thermostat wired?

Looking forward to your response.

Thanks,

Edward

[ab22]

• 3rd Gen 
• UK
• Nest is usb to plug socket, not hardwired 

thanks

[CAmerica]

Has any community specialist provided a detailed answer in the last 4 weeks?

I am looking to use same on a Baxi 836 and USB to Plug as per ab22.

Any updates?

[Johnny1901]

Have you removed the 240v link wire in the terminal block? If you do not then the boiler will turn on constantly until you turn off the mains power. This link must be removed if any external controls are used.

[StanG]

Hello,

Did you leave original thermostat connected?

On my Baxi nest installation, I left the baxi thermostat connected, installed the nest, but for the nest to work I had to change ambom setting on the baxi thermostat from 1 to 0. 

[StanG]

not sure if this helps or not, but this is what I did.

Baxi Luna 3 Ok
in order to make it work, you need to remove the jumper of the remote thermostat,
put F10 = 00, connect to the connector CN7.

1. If Baxi AVS77 thermostat is installed on the boiler, no problem, leave it there, also on my boiler
the AVS77 was connected to the M2 (optional connection) terminals 1 & 2.
2. If Baxi AVS77 is installed in the house, remotely from the boiler, you must install it on the boiler.
3. To install on boiler, the AVS77 is made to fit on the Baxi Boiler cover, use your existing wires,
that run from the boiler to the thermostat in the house, and just cut the wires off, when you mount the AVS77
on the boiler.
4. This boiler was made to operate with the AVS77, so it must remain connected to the boiler, I could not figure
out how to completely remove it, but installing on the boiler cover is a simple process,
and you do retain all the AVS77 controls, settings, water temp, hot water temp, etc.
5. OK, so now you have installed the AVS77 on the boiler, in order to install a Nest Thermostat,
and for it to work, you have to change 1 setting in the AVS77. On the AVS77 thermostat, press top left
button three seconds to access "IP Settings" then press OK button until "AMBON" appears on the screen,
you should see also a number "1" on the display, press the minus button and change setting to zero "0",
then press IP button again to save this setting. Doing this you are telling the boiler that the AVS77 is
installed on the boiler. Also by doing this, it enables you to install another thermostat in your house.
6, I installed the Nest Heat Link, 1 meter from the boiler. I connected the N & L wires to the Heat link for power,
I did not use the N & L wires on the boiler I basically connected a two wire extension cord to plug into an
outlet close by.
6. I connected two wires from the BAXI boiler M1 Connector, terminals 1&2 to the Nest Heat Link terminals 2 & 3,
then I connected my old existing thermostat wires to T1 & T2 on the Heat link, and installed the new Nest
Thermostat where my old AVS77 thermostat was installed in the house, and connected existing 2 thermostat wires
to thermostat base.
7. I installed the nest thermostat, and went thru the installation menu, I selected "combi boiler,
during the installation. New Nest thermostat works great as advertised, and I have the old AVS77 thermostat
still on the boiler to make any changes to the boiler setting that I may need.
I hope this info helps any future Nest Installations with a BAXI boiler with AVS77 thermostat.