3rd generation manual on did not turn on the boiler

[Shane2004]

I have two nest thermostat: one for upstairs and one for downstairs, recently the downstairs heating stop working even I forced it to be manual on (the boiler did not start), the upstairs is perfectly fine. I am not sure what went wrong, any help will be appreciated. 

[Shane2004 · Accepted solution]

Found out the issue was caused by a faulty Honeywell zone valve not nest system.  

[Markjosephp]

Hello Shane2004,

Thanks for posting and for updating us on what you've done to have your concern rectified. I wanted to see that you were good to go. Please let us know if you have any further questions; otherwise, we'll close the thread in 24 hours.

Thanks,

Mark